General IT stuff....

How to edit configuration files using "wrfile" command in NetApp DataONTAP.

2011-07-05T21:13:00.006+05:30

DataONTAP does not include an editor such as 'vi' in most standard UNIX like distributions. In DataONTAP, to edit any file from the console you need to use "wrfile" command, but this command can either overwrite or with -a option can append to a file. Hence, in order to edit/modify the file you need a workaround. However, if you have setup CIFS/NFS then you can easily edit any files using your favorite editor such as word.

Following example shows steps to edit the file from the DataONTAP console.

1. Open telnet/rsh Or ssh to the filer console (with putty for example)

2. Type

Filer>rdfile /etc/rc (For example)

Or whatever file you want to edit. It will print out the current contents of the file.

Note: To be on the safer side, make a copy of the file before editing the current one.

Filer>mv ./etc/rc /etc/rc.back

3. Copy the content of the rdfile output to a Notepad or other text editor.

To do that: Click the the telnet/putty's top left side corner. Menu will drop down: Edit > Mark and then Edit > copy & paste to the notepad.

4. Edit/change anything you want in the notepad.

5. When you're done, type

Filer>wrfile /etc/rc

6. press enter

7. Then QUICKLY copy/paste your modified text into the telnet/SSH console

8. Press CTRL-C to save the file and you're done.

Try "rdfile" again to ensure the changes were correctly saved.

Note: If you forget to do CTRL-C at the end you will remain in "wrfile" mode and everything you type will end up in the file you tried to edit. Therefore make sure you press CTRL-C at the end.

I have bought 160GB USB Drive, but why I only get a disk size of 149 GB, where is the remaining 11 GB gone ?

2010-03-26T23:21:00.007+05:30

Well, the answer lies in how the bytes are interpreted. Disk Manufacturers use "Decimal" as a base for calculation (i.e Base 10).

10^3 = 1000 bytes = 1 KiloByte , 10^6 = 1000 KB = 1 MegaByte , 10^9 = 1000 MB = 1 GigaByte

Whereas, the actual utilization is calculated using "Binary" as a base for calculation (i.e Base 2).

2^10 = 1024 bytes = 1 KiloByte , 2^20 = 1024 KB = 1 MegaByte, 2^30 = 1024 MB = 1 GigaByte

Note: Hard Disk Manufacturers will use 1000, not 1024 as base.

In this case, my USB drive has total bytes equal to = 160,039,239,690 Bytes. And we know 1 KB = 1024 Bytes, 1MB = 1024 Kilobytes, 1GB = 1024 Megabytes.

Hence, the total actual capacity comes to = 160,039,239,690 / 1024 x 1024 x 1024 = 149 GB.

In general, the capacity of a hard disk can be calculated using this formula:

Total Size of the Disk (Bytes) = (Cylinders) X (Heads) X (Sectors) X (Bytes per Sector)

Virtual Floppy in a Virtual World:

2010-03-09T14:04:00.011+05:30

Until a few years back (probably a decade), as far as i remember there were not many known options but to test on the bare metal physical box and re-image everytime its screwed due to some stupid work of experimentation. With the advacement of virtualization everything seems possible now, I am glad that i got exposed to 'vmware' few years back, i am really impressed with their long range of vmware products, i think what they have provisioned is trully revolunitoary.

Today one can play, emulate , crash , rebuild and learn as and when you want it without actually entering the IT hardware labs or a desktop machine at your home. One can install vmware products on the laptop (of course you need to ensure the minumum system requirements that each vmware products demands) and turn your laptop into a mobile testing lab.

There are no worries about re-imaging in case something going wrong and your system comes down crashing . In other words, without changing the physical state of your box (PC) you can now setup your own test environments. There is loads of information on the net about virtualization, you may also visit the vmware website to obtain more information about virtulization and vmware products. I chose 'vmware workstaion' product for my testing environment, and have been using it for past 2 years and i am really happy witht its usage.

However, my objective here is to show one of the useful feature in vmware called "virtual floppy" drive. If you are thinking that floppy disks are "dead", right ? Well, you are absolutely correct that the physical floppy 3.5" disks (or physical floppy disks of any size) are not used anymore. In fact none of the PC vendors are providing this provision anymore but they are replaced with what is called "virtual floppy drives".

They provide many advantages over traditional floppy drives. Some of the advantages of using virtual floppies are:

Ability to boot OS and applications.
Ability to transfer files between systems .
Does not get damaged, as there is no physical state.
Can even be sent as attachment over the internet.

In this article, i will show you how to use virtual floppy drives with VMware Workstation product.

Whether you are a system admin, student, or from Quality Assurance department , you would be presented with scenarios wherein you will be required to test certain application, applicaiton feature(s) or at the least you want to try out few experimental stuff for learning purpose. One of the most important learning steps in System Admin's life is to learn to recover system from crash. More often than not, floppies comes handy in such rescue operations, especially if the system's MBR is currupted and you are unable to boot the system.

You must be wondering even if i have a virtucal floppy drive on my vmware workstation, how do i actually get the virtual floppies to work with. To do this , all you need is a vmware workstaiton runing any flavour of Unix or Windows OS as a gues operating system and a 'notepad' in the as we know in Windows.

Steps to create and mount 'virtual floppy' on your vmware workstaion:

1. Right click on the desktop and create a 'notepad'
2. Rename the "notepad" to any name, in this example i have named it "virtual-floppy", and ofcourse we need to change the extension of the notepad to "*.flp", this is the standard image format that vmware understands.
3. Go to your vmware workstaion, click on edit settings, click on the floppy drive, if it's not there then add it using "add" option under Hardware. Click 'browse to select the image we just created, in this case "virtual-floppy.flp".
4. Start the vmware workstaion, and wait untl it boots up to desktop screen (FYI: I am running Redhat linux as gues OS on vmware workstaion 5).
5. Now, we need to format the floppy with a filesystem and mount it.

The most commonly used tool is : mkfs
mkfs ("make a filesystem") is the standard Unix command for formatting a disk partition with a specific filesystem.

The basic syntax is:
mkfs -t type device , where type is the type of the filesystem and device is the device the filesystem will reside on.
The most commonly used option is -t, which is followed by the type of filesystem to be created. If this option is not used, the default is ext2 (second extended filesystem). Among the other types of filesystems that can be created are ext3, minix, msdos, vfat and xfs.

As an example, the following would create an ext2 filesystem on a formatted floppy disk that has been inserted into the first floppy drive:
mkfs /dev/fd0

The following would be used to create a vfat (i.e., Microsoft Windows-compatible) filesystem on the floppy disk.

mkfs -t vfat /dev/fd0
We will go for the "-vfat" option as this is both Unix and Windows compatible.

Now that our floppy is formatted and ready, we can copy files to it as if, it is physical floppy drive. The most importnat need of of floppy that i can think of is during emergency or when your system is crahsed and you need to get it back somehow. The fastest way to get your system back is to have a 'bootable floppy' handy with you.

When it comes to bootable floppy, there are lot of boot loaders, but GRUB stands out, perhaps the best bootloader among all. Let's install the GRUB on the floppy that we formatted in the last steps. For that, we need to mount the floppy, create a folder by name 'boot' and 'grub' and then copy grub files (stage 1 & 2) from the local disk to floppy disk grub folder.

mkdir -p /floppy/boot/grub
cp /usr/local/share/grub/i386-pc/stage* /floppy/boot/grub
Or
cp /boot/grub/stage* /floppy/boot/grub

Note: Always ensure the correct path to the grub folder, it may be differnt on your system.

Finally, we need to install the grub on the Floppy disk.
Start the executable at the Linux command prompt by typing :
grub
enter the following series of commands at the grub prompt:
grub> root (fd0)
grub> setup (fd0)
grub> quit

We are done, we have now created a bootable virtual-floppy to work with virtual machines on the vmware application.

What is ports ? Ports are ports whether it is windows or Unix.

2010-02-10T15:00:00.005+05:30

Let's start with the basics. In the TCP/IP protocol stack, messages associated with the common application protocols that most of us are familiar with — such as HTTP for the Web; SMTP, POP, and IMAP for e-mail; Telnet and SSH for remote logon; and FTP for file transfers — operate over the Transmission Control Protocol (TCP) or User Datagram Protocol (UDP); TCP and UDP messages, in turn, are carried inside Internet Protocol (IP) packets. The primary difference between TCP and UDP is that TCP is connection-oriented and UDP is connectionless. When using TCP, then, two hosts must first establish a logical connection before they can exchange data (analogous to establishing a telephone connection) while hosts using UDP do not require a logical connection before the exchange of information (analogous to sending a letter through the postal service).

Both TCP and UDP employ port numbers to identify the higher layer applications at the hosts that are communicating with each other. End-to-end data communications on the Internet, in fact, are uniquely identified by the source and destination host IP addresses and the source and destination TCP/UDP port numbers.

TCP/IP applications generally employ a client/server model, exemplified by the relationship between your Web client software (i.e., the browser) and a Web server; the user "points" their browser at the Web server which is usually listening on port 80. Port numbers can take on a value between 1 and 65535, with server applications generally being assigned a value below 1024.

There are a large number of so-called well-known ports, including:
TCP 20 and 21 (File Transfer Protocol, FTP)
TCP 22 (Secure Shell, SSH)
TCP 23 (Telnet)
TCP 25 (Simple Mail Transfer Protocol, SMTP)
TCP and UDP 53 (Domain Name System, DNS)
UDP 69 (Trivial File Transfer Protocol, tftp)
TCP 79 (finger)
TCP 80 (Hypertext Transfer Protocol, HTTP)
TCP 110 (Post Office Protocol v3, POP3)
TCP 119 (Network News Protocol, NNTP)
UDP 161 and 162 (Simple Network Management Protocol, SNMP)
UDP 443 (Secure Sockets Layer over HTTP, https)
A complete list of port numbers can be found at the Internet Assigned Numbers Authority (IANA) list of port numbers at http://www.iana.org/assignments/port-numbers.

Next quetion arises, how do you find out which port is being used , or if that port is listening or free.

For Windows - most handy command is - netstat -a (This works for UNIX as well)
For Linux - Apart from netstat -a , there are more.
1. netstat -an grep 'portnumber' (There is a pipe between grep and portnumber)
2. netstat -a grep 'portnumber' (There is a pipe between grep and portnumber)
3. lsof -i: 'portnumber'

A port scanner, most simply, probes a computer system running TCP/IP to determine which TCP and UDP ports are open and listening, which indicates all of the services that this system is offering to other TCP/IP hosts. As an example, you would expect an e-mail server to be listening on the SMTP and POP3 ports, and a Web server to be listening on the HTTP, and perhaps the SSL/HTTPS, ports. For good or for bad, however, most systems have many more open ports than intended. You can use the netstat -a command to find out which ports are open on a local Linux/Unix or Windows system but netstat can't be used remotely across a network.

Port scanners can also be used to examine hosts for known Trojan horses, distributed denial-of-service (DDoS) tools, or other malicious services running on a host.
A short list of some of the default "bad" ports are:
1243/tcp: SubSeven server (default for V1.0-2.0)
6346/tcp: Gnutella
6667/tcp: Trinity intruder-to-master and master-to-daemon
6667/tcp: SubSeven server (default for V2.1 Icqfix and beyond)
12345/tcp: NetBus 1.x
12346/tcp: NetBus 1.x
16660/tcp: Stacheldraht intruder-to-master
18753/udp: Shaft master-to-daemon
20034/tcp: NetBus Pro
20432/tcp: Shaft intruder-to-master
20433/udp: Shaft daemon-to-master
27374/tcp: SubSeven server (default for V2.1-Defcon)
27444/udp: Trinoo master-to-daemon
27665/tcp: Trinoo intruder-to-master
31335/udp: Trinoo daemon-to-master
31337/tcp: Back Orifice
33270/tcp: Trinity master-to-daemon
33567/tcp: Backdoor rootshell via inetd (from Lion worm)
33568/tcp: Trojaned version of SSH (from Lion worm)
40421/tcp: Masters Paradise Trojan horse
60008/tcp: Backdoor rootshell via inetd (from Lion worm)
65000/tcp: Stacheldraht master-to-daemon
http://www.garykessler.net/library/bad_ports.html
Courtesy : http://www.garykessler.net/

Test disaster recovery (MBR curruption) of Redhat AS 4 on vmware workstation 5:

2009-02-20T15:57:00.015+05:30

Test disaster recovery of Redhat AS 4 on vmware workstation 5:

Test Disaster Recovery Procedure:
1. Backing up MBR.
2. Currupting the MBR.
3. Booting off the Live CD.
4. Mouting root file system.
5. Restoring MBR from the backup in step 1.

Step 1: Backing up Master Boot Record (MBR)

What is MBR:
The MBR is a 512 byte segment on the very first sector of your hard drive composed of three parts: 1) the boot code which is 446 bytes long, 2) the partiton table which is 64 btyes long, and 3) the boot code signature which is 2 bytes long.

Using dd command we will be backing up the MBR which consists of 512 bytes.

What is DD:
Disk Definition (dd) came from IBM's Job Control Language and became a staple of the low-level UNIX and Linux commands. What dd does is copy bytes from an input source (if) to an output source (of). But dd can also copy raw data as well, which makes it perfect for copying boot sectors. The dd command can handle many tasks including: disk cloning (Note: Target disk must be of equal size or greater than the original disk)disk imaging,partition cloning, restoring from image file.

[root]# dd if=/dev/sda of=/backup_of_mbr bs=512 count=1
1+0 records in
1+0 records out
[root]#

For IDE devices: Its hda, for SCSI devices: its sda, check your scenario.

I have backedup MBR on the root. It's advisable to backup MBR to an external disk such as USB, CD or a differnt drive.

Step 2 : Currupting the MBR.

We will kill the MBR but leave the partition table intact by simply currupting the boot-code of 446 bytes of the total 512 bytes.

[root]# dd if=/dev/zero of=/dev/sda bs=446 count=1
1+0 records in
1+0 records out
[root]#
For IDE devices: Its hda, for SCSI devices: its sda, check your scenario.

Error on the reboot:

The master boot record (MBR) of this virtual machine's hard disk does not contain valid bootstrap code. It is likely that the MBR was corrupted by an incorrect guest operating system installation or some other reason. The virtual machine cannot continue and will now power off.

Step 3 : Booting off the Live CD or from an ISO image of the CD.

If you have a Live CD then simply insert the CD into the Drive and start the vmware machine. Note: make sure vmware has the control of the CD-ROM drive at this momment.

Or,

In case you have ISO image, then click on "VM" on the top menu bar of the vmware panel and select -"settings" | Click on CD-ROM under device | select "use ISO Image" | Browse to the ISO image of the Live CD.

Start the vmware machine.

Step 4: Mouting root file system.

a.You will be presented with redhat linux install options - In the command line Type : linux rescue [Enter]
b. Next sceen will ask you to "choose a language" , select "English" [Enter].
c. Select a keyboard type - choose "US" [Enter]
d. Do you want to start network interface on this system - Its up to you, i said NO b'cos i don't need a network, scope of this test is to Fix the currupted MBR.
e. You will now be presented with "Rescue" screen with following message :

The rescue environment will now attempt to find your linux installation and mount it under the directory /mnt/sysimage. You can then make any changes required to your system. If you want to proceed with this step choose 'continue'. You can also choose to mount your file system 'read-only' instead of read-write by choosing 'read-only'.

From the three options : Continue | Read-Only | Skip , Choose 'Continue', b'cos we want to mount the file system in read-write mode.

In the next screen "Rescue" , following message is displayed : Your system has been mounted under /mnt/sysimage . Press to get a shel. If you would like to make your system the root environment, run the command:

chroot /mnt/sysimage

Press [Enter]

Following message is displayed in the next screen :
Your system in mounted under the /mnt/sysimage directory. when finished please exit from the shel and your system will reboot.

-/bin/sh-3.00# [This is the shel you wil get, enter the following command]
-/bin/sh-3.00# chroot /mnt/sysimage

sh-3.00# [Now you are back in business, just type 'ls' to get the list of items and to see the backup file you created in step1].

sh-3.00# ls [Enter]
backup_of_mbr boot halt lib misc proc selinux tmp
backup dev home lost+found mnt root usr
bin etc initrd media opt sbin sys

You can see the backup file 'backup_of_mbr' up there...

Note: I hope you remember i saved the backup file 'backup_of_mbr' on the root itself that is - "/".

Step 5: Restoring MBR from the backup done in step1.

At the following shel type :

sh-3.00# if=backup_of_mbr of=/dev/sda bs=446 count=1
1+0 records in
1+0 records out
sh-3.00#

Finally, remove the "live cd" or "ISO image" and type "exit" at the shel command, and once again type 'exit' as shown below:

sh-3.00# exit [Enter]
-/bin/sh-3.00# exit [Enter]
logout..
rebooting the system....

That's it - You are back in business, your linux will boot off normally as if nothing happend. This was a very small excercise to demonstrate how to overcome currupt MBR issues as long as you have a proper backup of the same. Iam a beginner in linux hence there may be mistakes which i don't know untill someone points to me but i hope i will learn as i grow further.

Free VMware Workstation without the need to create your own virtual machine:

2009-01-21T15:57:00.007+05:30

To help you get the most out of your free evaluation of VMware® Workstation, here is the quick easy way to get your first virtual machine up and running.

Try VMware Workstation without the need to create your own virtual machine, you can download a free "virtual appliance" with Linux .

Download a free "virtual appliance: (Linux OS + Firefox browser pre-installed)

http://www.vmware.com/appliances/directory/80?src=EM_08Q4_VMW_OTHER_WORKSTATION-EVAL-CAMPAIGN_EM2&ossrc=EM_08Q4_VMW_OTHER_WORKSTATION-EVAL-CAMPAIGN_EM2&elq=C1416441A8CA488BA692DCEE197DB9BA

Courtesy:VMware

What is virtualization ? By, Vmware.

2009-01-15T09:38:00.009+05:30

Virtualization is a trend that is sweeping enterprise IT across the globe. Overall 7 million servers are shipped every year world wide. Out of those 6 million servers are Intel Architecture X86 and these are getting deployed in the enterprise data centres world wide. In a traditional environment there are single application running on single OS on a single machine and they are sprawled across the data centres, this leads to a tremendous cost in the number of areas - in terms of Hardware, data centre facility cost, interms of operational maintainance and management cost.

To address this overwhelming pressures, what enterprise IT has found is the most compelling tool called "Virtualization Technology" (VT). Across these millions of single servers the average utilization is just about 5-10%. This indicates they are barely utilized to its capacity. So what VT does it allows you to take advantage of this under utilized resources as well as the fine granined technology to RUN these envrionments side by side on much lower number of PHYSICAL SERVERS. To illustrate this, we take these environments it could be databases, webservers, e-commerce application, business application and you take them and consolidate them into much smaller number of physical servers. Each of these environment now runs side by side on a single machine and each of them is fully isolated and encapsulated.

What that means is - There is a Hardware Layer and top of it is the "Virtualization Layer" that enables all this and on top of this you have each of these environments whether it is databases,webservers ,business applications etc. They all have their separate operating-system (It coud be UNIX, LInux, Windows, Solaris etc) and on top of this runs each of this applications side by side on the single machine. The most facinating this is that - each of this virtual servers has its own CPU, memory, ethernet Nic, disk. They all run in a isolation just as they would run in a physical enviornments.

What all this means to IT companies is - Tremendous savings. Earlier IT organizations use to run 800 servers for various applications are now able to consolidate that down to just 60 servers. ROI is tremendous.

In addition to that, it also completey changes how customers can provision their application, their server environments. For example - How you initiated new server, new applicaiton softwre earlier...? Putting this out into your data center took number of weeks - to procure the hardware, to install the OS and then patch it with service packs, install the application and confifure that. Phew!!!!

Now all these is a software, hence initiating this is a matter of minutes.

Basic's of storage networks (An insight into - How we got to, where we are today..')

2009-01-14T21:55:00.001+05:30

SAN explained in most simplest way.......

2008-04-04T01:45:00.000+05:30

There are loads of books on Storage especially Storage Area Network (SAN) but very few can explain SAN in few words that too in a lay man method. Well, i really appreciate Gary for this piece of information, the way he walked through the LAN network , followed by SAN in just 4 odd minutes, applaudable . Even my Grandma understands what is SAN now.

Thanks, Gary.

Courtesy: Youtube.

All SAN aspirants, a peek inside the server room, check this out.

2008-04-04T00:39:00.000+05:30

Usually, its difficult for the fresh IT proffesionals trying to break into SAN career to get inside the server room and play with big toys (machines) unless you are a freelance consultant, or directly employed with the IT company.

This is a cool video for all those who wants to get a feel of SAN technology to start with..

Courtesy: Yotube

Welcome to the world of virtualization: vmware

2007-11-30T11:46:00.000+05:30

Problem: More work on less hardware , with less people and less time.
Solution: Vmware virtulization.

What is virtulization:
The software layer providing the virtualization is called a virtual machine monitor or hypervisor.
Its basically a emulated set of hardware, they just give u virtual hardware environment, you need to install the real operating system and real application. They dont give u packed-up vesion of OS, no, they are not giving you virtual OS, its virtual hardware . Iam here talking about the vmware-workstation product. They just take the existing hardware and present to you as new set of hardware (virtual) , you need to install the real OS and applications on top of it.

Note: Applications & OS are real, only hardware is emulated.

With vmware, you can have multiple applications in your single machine, independent of each other, each application has its own OS and own set of virtual hardware. virutal hardware is identical where ever you go, virtual machine can be moved from machien to machine , b'cos of the hardware independece between the virtual machines.

Virtual hardware:
CPU:CPUS is something they dont emulate, CPU is allocated to different virtual machine, therefore they pass the instruction directly through from guest OS (virtual machine) down to the physical processor.

Memory: Memory is something they don't emulate, , memory is allocated to virtual machine, but the instructions are again sent thru to physical memory but, they do emulate all the other hardware like :Network card, serial & parallel ports, cdrom, floppy drive ,key board, mouse etc.

Now, with vmware , you can have multiple applications on the single host OS, b'cos they have their own virtual hardware, own protected memory and own environment, independent of other virtual machines. They are completely isolated machines, if anything happend to one virtual machine ,it does not affect the other virutal machine or the host OS.

Real world problem : You have a OS, which has complete control over the hardware, which then parcels out the resources to one or more applications. There are two problems with this ,which hurts the management of this system.

Application is completely dependent on OS configuration, different Applications means different service packs, OS service packs, and they can even crash the hardware if they misbehave with the OS, and they could misbehave in terms of driver, service packs, etc. Different applications shares the same hardware, so they can not work well together.

Os is tied to the hardware, thru its driver, kernel, because of its dependence on the hardware, it can not be moved easily, where as vmware virtual machine is basically a "file", therefore it can be moved to another mahine in matter of seconds, b'cos of its hardware indepedence across all hardware platform , across all os, the vmware emulated hardware remains the same.

Feature : Paritioning
1. Run multiple OS on one physical machine.
2. Fully utilze server resources.
3. SCSI reservations enable clustering.

Feature: Isolation & Workload Management
1. Key: Uses CPU harware (Protection)
2. Fault, performance, and security isolation.
3. CPU, RAM, Disk, and network resource controls.

Feature: System Encapsulation
1. Entire state of the VM is encapsulated: (Memory, disk images, I/O
device state)
2. VMs state can be saved to a file: (Checkpointing, aka "suspend/resume"
3. VM state can be transfered thru time and space :(Time: Store in a file, Space: Transfer over a network)

For more information on this cool technology, you can visit: http://www.vmware.com/

What is GRUB, it is the first thing you see When you boot Solaris, Redhat or other UNIX-like distro..

2007-08-17T12:30:00.000+05:30

GRUB is currently available under the GNU General Public License as "free" software, free to share and change. Project was launched in line of creating a free 'boot loader'.

GRUB: GRUB orginated in 1995, when Enrich Boleyn was trying to boot the GNU Hurd with the University of Utaha's Mach 4. Enrich then began modifying the FreeBSD boot loader, so that it would understand Multiboot. He soon realized that it would be lot easier to write his own boot loader from scratch than to keep working on the FreeBSD boot loader, and so GRUB was born.

GRUB:(GRand Unified Bootloader), is a boot loader package from the GNU Project, it allows a user to have several different operating systems on their computer at once, and to choose which one to run when the computer starts. GRUB can be used to select from different kernel images available on a particular operating system's partitions, as well as to pass boot-time parameters to such kernels.

GRUBcan run on any operating system with a Multiboot kernel. It is predominantly used on Unix-like systems; the GNU operating system uses GNU GRUB as its boot loader, as do most general-purpose Linux distributions. Solaris has been able to boot using GRUB since version 10 (1/06 release).

GRUB: (Features)1. Basic funtions must be straightforwad for end-users.2. Rich functionality to support kernel experets and designers.3. Backward compatibility for booting FreeBSD, NetBSD, OpenBSD, and Linux . Proprietary kernels such as :a. DOS.b. Windows Nt.c. OS/2 ,
Are supported via a chain-loading fuction.

Courtesy:www.gnu.org

Linux is a "KERNEL" not an Operating System :

2007-08-15T19:03:00.000+05:30

Kerel(Linux) is a part of Operating System (GNU) :

For the past one year, i have been working with UNIX-like distros.., but i never give it a thought to know the difference between a "kernel" which is a linux and the Operating System which is a GNU, untill i came across a document by Richard Stallman, that corrected my "wrong" assumption of Linux as OS.

http://www.gnu.org/gnu/linux-and-gnu.html,

So, what is Linux:
Friends, Linux is just a "kernel", it can only function in the context of a complete operating system.( Kernal definition: The program in the system that allocates the machine's resources to the other programs that you run).

The "kernel" is an essential part of an operating system, but useless by itself; it can only function in the context of a complete operating system. Many users are not fully aware of the distinction between the kernel, which is Linux, and the whole system, which they also call “Linux”.

In simple layman words:
GNU an "UNIX-LIKE OS" was already created as a complete OS, with "Hurd" as a kernel in early 1990, but there were few problems with this kernel and it was still being developed, fortunately , it was during 1991, when "Linus Torvalds" wrote Linux (Free Unix like Kernel) and filled the last major gap, and that's all about it, Linux (kernel) together with the GNU system gave brith to a complete free Operating System called "GNU/Linux".

What is GNU:
If you are wonderfing what is "GNU", here is the information :GNU stands for “GNU's Not Unix. GNU is a project by community of people, conceived in 1983 as a way of bringing back the cooperative spirit that prevailed in the computing community in earlier days—to make cooperation possible once again by removing the obstacles to cooperation imposed by the owners of proprietary software, the main object was to create "FREE" software.

By "Free" it means:
Software that comes with permission for anyone to use, copy, and distribute, either verbatim or with modifications, either gratis or for a fee. In particular, this means that source code must be available. “If it's not source, it's not software.

Courtesy: Richard Stallman

Love Linux not necessarily marry : -Ashwin

2007-08-10T16:48:00.000+05:30

I am not undermining linux by that statement, but it's just a thought for all those who have never seen or experienced linux, there is a complete new world of Operating System which is Bug free, spyware free and virus free. It is not necessary that you swtich to linux based OS, but you can always give it a try, and see the difference yourself.

When i say love linux, i actually meant, experience it, see the difference yourself, and then decide what you wnat to do, i think that's a fair statemetn . To being with, you can either have it installed on the other partition of your PC so that you continue to use the existing os and yet get the taste of Linux. In case you do not want to part way with your Hard disk for whatever reason, you can get a copy of VMWARE application (http://www.vmware.com/) installed on your system and run the virtual image of Linux, this is what i have been doing for past one year, this tool gives you the freedom to use/test different types of Linux distros.

Like most of us, i always feared of UNIX-like OS, b'cos of its resemblance with UNIX, and i always imagined UNIX administrators running through complex commands via command line interface , and i always asked myself, without any knowledge of commands, how am i going to find and run my favorite applications, how am i going to deal with listening to audio or watching movie, these were some of my fears when i thought of UNIX from a beginners point of view.
I googled and found lot of stuff about Linux, soon i got to know that, there are window packages that gives you Desktop-Environment similar to Windows so that you can easily work through your Linux, A “desktop environment” can mean anything ranging from a simple window manager to a complete suite of desktop applications, such as KDE or GNOME.

So, Soalris / Redhat / Ubuntu.. all can have a desktop :) , for this article, we shall only concentrate on one such application called GNOME:

What is GNOME:
Acronym for GNU Network Object Model Environment. (Pronounced guh-nome.) GNOME is part of the GNU project and part of the free software, or open source, movement. GNOME is a Windows-like desktop system that works on UNIX and UNIX-like systems and is not dependent on any one window manager. The current version runs on Linux, FreeBSD, IRIX and Solaris. The main objective of GNOME is to provide a user-friendly suite of applications and an easy-to-use desktop.
http://en.wikipedia.org/wiki/GNOME

In case you want to work from command-line, no one is stopping you : Just open the "Terminal", and play with commands if your main purpuse is to deal in commands. That's it, i installed redhat, and got familiar with the look of it, what is where etc, but i must say, its so quick and easy to work through commands, and it is not tough, its just a matter of getting use to, i googled to look for article on the web and found of milions of page dedicated to Linux and linux forums where you can get direct help from other Linux users, i slowly started working with commands, and in the process, i learnt , how to "unzip" (gunzip) file in Linux, what is "Kernel" , "Directory structure" , "daemons (Programs) " ,"services", "Libraries" , "tar" , what is "package", how to move/ copy/ delete / edit / how to setup FTP etc . It was slow process, but i did not mind b'cos my jod did not depend on it, i was learning it as a hobby, which indeed made me more relax and patient and that helped me in digging further in to "UNIX commands".
Over the past year, since i first saw the Linux, i have worked on Redhat, ubuntu and solaris and believe me, most commands work the same on these different flavours, therefore handy unix commands will help you anyday on any flavours. For those who are least interested in commands, and just looking for more reliable, bug free environment and yet wants to retain the user friendly features of Windows can always work with window managers provided by KDE/GNOME.

I still consider myself a novice here, but that does not mean complexity on the linux side , i just like to be like that, Linux is a journey for me not a destination , discovering virus free environmetn where my pc not only works faster than before it even runs similar applications like Office (word, excel, powerpoint) which i have been use to for ages. Further, you never know when this extra bit of skill will come handy at your current job space, or even lend you a better job than the one you currently have. So, why shy away, go ahead and befriend Linux.

We all feel good, when we work through command line, don't we ;) , even though same can be achieved via GUI, because that lifts our confidence in the command-line world . On this point let me introduce you to what is called :Terminal, command line, Shell etc.

The command line is also known as the terminal or the shell. People also call it a terminal window, or a shell prompt, or a command prompt.

Terminal window = command prompt = shell , its one and the same.Running a command, means typing something at the command prompt then pressing the ENTER key to execute the command.

Let's take a look at some of the basic commands that are the most useful:
1. View directory contents with 'ls'
'ls' command, the purpose of this command is to list the files that are in the current directory. At the command prompt, type in 'ls' without the quotes. Then press the ENTER key. You will see a list of files that are in the current directory. Let's look at an example of how to use this command:
user@linux~> ls

2. Make a directory with 'mkdir'
How can we create a directory? There is a command called 'mkdir' that is used forthis. You use this command using this as a pattern:
mkdir [insert directory name here]

3. Remove a directory with 'rmdir'
Once we have made a directory, can we remove it? Yes. We use the 'rmdir'command. This command is similar to the 'mkdir' command in regards to how to useit:
rmdir [directory you want to remove]
You just replace the "[directory you want to remove]" with the actual name of the directory you want to remove. For example:user@linux:~> rmdir myfiles

4. Change to a directory with 'cd'
Let's say that we have just created a directory called 'myfiles'. How do we then go into that directory? This is what the 'cd' command is for. It is used to "c"hange"d"irectories. This is how we will use this command:
cd [directory name]

How do we get back out of the directory? Instead of providing a directory name,we just put in two dots for the name. This just means, "I want to leave the directorythat I am currently in." This is what using the command looks like:user@linux:~/myfiles> cd ..

5.What directory am I in? Using 'pwd'
How do we know what directory we are in? There is a very simple command forthis. It is called 'pwd'. That just means "p"resent "w"orking "d"irectory. You use itlike this:
pwd

And it tells you what directory you are in. Using this command will help youknow if you are in the right place.

6. Copying files with 'cp'
Now that we know some commands for working with directories, let's look atsome ways to work with files. To begin with, we will look at copying a file. Thecommand 'cp' will do this for us. Its usage is thus:
cp [source file] [destination file]

You just replace "[source file]" with the file you want to copy. You replace the"[destination file]" with the place you want that file copied to. For example, if I hada file called 'mybooks.txt' and I wanted to make a copy of it called 'somebooks.txt', Icould run this command:
user@linux:~> cp mybooks.txt somebooks.txt

7. Moving files with 'mv'
If you want to move a file instead of copy it, you can use 'mv'. The syntax ofhow to use this command is very similar to the 'cp' command:
mv [source file] [destination file]

Replace "[source file]" with the name of the file you want moved. Replace "[destination file]" with the filename you want it moved to. You may notice that you can also use this command to rename a file, "moving" it from one filename to another. Example:user@linux:~> mv myfile.txt yourfile.txt

8. Deleting files with 'rm'
What about if we want to delete a file? This is the purpose of 'rm'. Thiscommand will permanently remove a file, so be careful with it. The way you use this is as follows:
rm [file to delete]

Again, use caution with this command. Its effects are permanent. Here is anexample:user@linux:~> rm myfile.txt

9. Viewing text files with 'cat'
Many files in Linux are text files. How do we view the contents of such textfiles? If the file is relatively small (its contents won't fill up more than one screen),we can use the 'cat' command. This command will just output the contents of the filestraight to the screen. Its usage is as follows:

cat [filename to display]

10. Viewing text files with 'less'
What if the file is too long to fit on one page? If it is a really big file, it may justdump large amounts of text to your screen. This will make it scroll up way fasterthan you can read it. Is there a solution to this problem? You bet. It is the 'less'command. This is how you use it:less [filename to display]

11. What time is it? What is the date? Using 'date'One very easy command is called 'date'. This displays the current date and time.Use this command as follows:

date

In addition to these commands, Sometimes, you will runinto a situation where you may need some help learning how to use a particular command. Fortunately, there is a help system built into Linux which can assist you with this. It is the 'man' command, which displays help on using other commands.

Using 'man' to find help

To use 'man', the following is the syntax:man [command]

Installing Samba on Solaris:

2007-08-04T22:47:00.000+05:30

Samba is a useful program to install if your Solaris machine is networked with other machines running Windows. It enables the Solaris system to appear in Network Neighborhood on Windows, thus enabling simple drag-and-drop transfer of files between the systems. Samba also enables the Solaris system to print to printers attached to a Windows system.

Samba is supplied in source form and you need to compile it. This isn't difficult! Before doing so, you need to have installed the g(un)zip program and a C compiler. All of these are freely downloadable from the Net and instructions for installing C and gzip are here.

Step by Step procedure:
http://www.kempston.net/solaris/samba.html

The source code of Samba is available from:
http://samba.org/

What is Telnet and SSH?

2007-08-03T23:58:00.000+05:30

What is Telnet and SSH?
Telnet and SSH allows you to access your shell account.

Are there any differences between TELNET and SSH?
TELNET and SSH has long been employed by end-users and system administers to remotely control his or her servers. The key differences is that TELNET establishes a plain text connection while SSH, or Secure Shell, uses an encrypted connection so no one can ears drop on what data is being received or sent.

If you need to connect to the web server hosting your web site then SSH is the better option of the two since security is always a major concern, particularly, for businesses. Also, you do not want to legally liable for any damage that may occur from your web hosting account being used for illegal activities.

Why SSH?

When you telnet to a machine and, say, type your password, every keypress of your password is relayed across the Internet to our server in cleartext. This means that if some nefarious person on one of the routers through which the information passes sniffed the packets (the Internet equivalent of "tapping" a phoneline), then they'd suddenly know your password, letter for letter!

With SSH, the information is encrypted. So when you type your password, each letter is "scrambled" before it's sent over the Internet, and decoded at the other end. The encryption method is such that, if someone in between the servers stumbled upon the information, they'd just see a jumbled noise.

As you might imagine, this increases your security significantly.

Port (Ftp): 20 & 21

Port (SSH): 22

Port (Telnet): 23

Where can I get an SSH client? (For Windows Platforms)

Putty is a small but fully featured Windows SSH and telnet client. http://support.positive-internet.com/software.php

UNIX:

1. Command for SSH ?
ssh user@host

2. Can I run backups over ssh?
Yes. The easiest possible way to do this is:
# tar cvf - ssh user@host "dd of=/dev/tape"

3. Can I use ssh to communicate across a firewall?

Yes. All you need is an open port on the firewall and the sshd or sshd2 listening on the other side. Most people do this on port 22 (the standard port for Secure Shell), but if you have a BOFH, you can also tunnel through another open port through the firewall (I'm sure all those system admins love me now :-) by running a daemon on the remote side on a port that's allowed through a firewall, like SSL (port 443).

Set up the remote daemon running sshd on port 443:
# sshd -p 443

Then, on your local system, open a connection on port 443:

$ ssh -p 443 remotehost.example.org

You can also use Secure Shell to tunnel insecure traffic like POP, IMAP, and others through the firewall as well.

Difference between BLOCK and FILE level Data : -Ashwin

2007-06-25T00:43:00.000+05:30

Block refers to Physical level, the way OS interacts with Disk-Drive, simplest example would be "OS interacting with local SCSI Harddrive in our home/office pc" . It deals with block of disk, there is no file-system attached to it. Clients can not read and interepret block-data if there is no internediate file system like ..NTFS, FAT, Ext3 etc.

SQL and Exchange: Are highly write and read intesive databases, in other words, they need faster processing because they process many read and write requests, (Online Transaction Processing) and thats why they deal in "Blocks". Therefore SQL and Exchange database is not recommended on "NAS" or "FIle servers", because these file servers are usually accessed as a mapped or UNC path and the data is moved via "TCP/IP" network and it deals in "File Level" protocol such as "CIFS/SAMBA" for Windows and NFS for (UNIX/Linux) paltforms which is not suitable for Databases applications.Block storage is normally abstracted by a file system or database management system to talk to clients or endusers.

Block based databases requires : Locally attached disk array Or SAN data centers.

File Level Data: The data which has file system attached, for example: a word document , is a file level data and is backedup along with this meta data. This is where NAS / Netapp / Windows Storage Server comes in to picture, they are basically "Read" intesive boxes. They are not meant for intensive writing, they are basically file servers providing file service (Read) to clients. For normal disk sharing between small Office / Home office this is a good option, where many users can write to and read to common "Disk" on the remote server via mapped or unc path.

File level : NAS / Netapp & Windows Storage Server.

Summary:
This file system can reside either on a server or on a NAS device. If it’s on the server, block level data is written to the disk array, usually via either an FC or iSCSI interface. If the file system is on the NAS, file level data is written to the NAS device, usually via Ethernet. The NAS device in turn writes block level data to disk. A “NAS Gateway” is a device that maintains the file system and communicates file-level data with clients on the LAN, while storing data on external FC-attached disk.

An advantage of file level data is the ease of sharing information. Because the file system resides within the NAS, any device can access and understand the data. When the file system resides in the server, only that server can retrieve data from the disk.

Affordable Windows iSCSI storage area network : Backup Exec backs up data to ISCSI drive.

2007-06-24T21:41:00.000+05:30

How to build an affordable Windows iSCSI storage area network, Here in this article, author has shown, how Backup Exec for Windows Server can make use of "NAS" Or another Server's Hardisk as backup drive and transfer data "Block-Level" via "ISCSI" protocol. This is faster than the orthodox "TCP/IP" file-level backup.

Courtesy:
http://www.crn.com/article/printableArticle.jhtml?articleId=59201007

Interview questions for tech companies : Crack it.

2007-06-21T12:16:00.000+05:30

Please visit the following website for any IT Support / Development / Aministrator's Job Interview Questions and Answeres.

http://www.techinterviews.com/

It's a wonderful site for those who are prepraring or in process on any forthcoming interview schedule. You can find interview related question's ranging from :

1. Exchange Domain
2. Databases.
3. Backup Administrator
4. Computer Hardware.
5. Testing.
6. Developer (C++, Java etc)
7. Networking.

Any, many more.

Courtesy: http://www.techinterviews.com/

NDMP ended the monopoly of the Backup software Vendors and File Server vendors :

2007-06-18T16:47:00.000+05:30

With the invent of NDMP, we have only one "universal agent" for the network- attached file servers to be used by any of the centralized backup administration applications. Earlier Backup vendors had to "develop" many cleint/agent software which would understand different OSes needs,

for ex:
1. Windows agent for Windows Servers.
2. Unix angent for Unix/Linux Servers.
3. Solarix agent for Solaris Servers.
4. Mac agent for Mac Servers.

This not only led to more cost incur on the vendor side for development of these agent, but also customers had to bear the cost of so many agents, further dedicated file servers had to be mounted to such OS so that their data could be backed via NFS or CIFS (SAMBA) file level protocols. Most serious drwabacks were , data had to travel via networks to the central backup application where "tape/library" was attached.

FIler Definition: -Ashwin

2007-06-14T19:12:00.000+05:30

Filer, is a storage device (cabinet) with an embedded processor and a "light weight" OS that exposes disk units to network-based clients (which are usually servers) . Clients that access NAS-based storage must also run some sort of redirector or client software that lets the OS see the NAS-based disk as locally attached storage.They are used in data sharing applications including the Internet, fibre channel SANs, and Ethernet LANs

Backup and Restore : By Dilip Naik

2007-06-14T18:54:00.000+05:30

Backup is the process whereby a coherent copy of data is made. Backup has become more important as the amount of data has exploded, not just in importance, but in volume as well. One study estimates that more data will be created in the next few years than has been created since the dawn of history! It is interesting to compare the growth in data storage with the more widely known and appreciated growth in electronic chip density. Recall that Moore's law implies that the amount of electronics on a given chip area doubles every 18 months. A lot of industry analysts believe that the growth in digital storage is actually handily beating Moore's law in the sense that the amount of data doubles in much less than 18 months.

Backup and Restore Technologies:
http://searchstorage.techtarget.com/
searchStorage/downloads/Naik_ch05.pdf

VMware Infrastructure 3 Demo: Magical Suite for IT People / Department.

2007-05-25T14:38:00.000+05:30

A live demonstration video that show you some of the solutions you can build with the VMware Virtualization Suite.

Features:
1. Running number of Virtual servers off the fewer Physical Server.
2. Run different OS off the same Physical Server, its hardware independent.
3. You can build Virtual Web-Server, straight on the fly.
4. You can create many test setups, straight on the fly using the templates.

You can watch this video right here,

Linux Filesystem Hierarchy - Part One , From Binarysignal

2007-05-23T23:42:00.000+05:30

Learning linux was never so easy, its great video for all the beginers or those who wants to learn or switch to Linux for their home or office computing.

Linux Filesystem Hierarchy - Part Two, From Binarysignal

2007-05-23T23:40:00.000+05:30

Continuation from Part one,

BAD PASSWORD: it is based on dictionary word | Linux password issues | -Ashwin

2007-05-21T16:20:00.000+05:30

The most reliable way to change your linux password is via a command prompt. You will need to start a terminal window. At the prompt, type passwd. You will be prompted to enter your current password, followed by the new password and the new password again. None of the passwords will be echoed on the screen.

If you do not see the message "authentication tokens updated successfully" there was an error changing the password. Just type passwd and try again. Pay careful attention to your typing.

You may get some errors: As shown in the Figure above .
BAD PASSWORD: it is based on a dictionary word

BAD PASSWORD: it's WAY too short or similiar.

That means your password doesn't meet the password requirements. Ideally it should be at least eight characters long, not based on a dictionary word and a mixture of letters, numbers and characters.

Solution: Incase you don't have time to think of any possible good password, make use of the "Online" password generator, the link is given below.

Random Password Generator, OnlinePasswordGenerator:
http://www.webcogs.com/passwordgenerator.aspx

Penguin Gallery : Funny, Cute and artistic penguins...

2007-05-19T23:05:00.000+05:30

Super-Penguin , Here is a collection of the interesting penguins we have been able to find out there on the net. Note that we're not trying to gather up every occurence of a penguin somewhere - the idea here is to catalog the "derivative" penguins that are on the loose. Please click on the web URL given below to see penguins in different imagination.

In the beginning, sometime in early 1996, several people were talking on the linux-kernel mailing list about a suitable logo/mascot for Linux. Of the many, many suggestions, many involved parodies of other operating system logo's - or were strong, noble beasts such as Sharks or Eagles. At some point (I'm not sure when), Linus Torvalds (the father of Linux) casually mentioned that he was rather fond of Penguins - which rather stopped the debate in its tracks.

Penguins Gallery:
http://lwn.net/Gallery/

Penguin the Linux Mascot : Story goes like this..

2007-05-19T21:15:00.000+05:30

Linus Torvalds, the creator of the Linux Kernel, was visiting his friend Andrew Tridgell, the creator of the Samba suite. They were walking through the Zoo in Canberra when, without warning, a huge flock of vampire attack penguins dove out of the sky and tried to carry Linus away. Fortunately, Andrew had an umbrella. Still, one of the birds was able to nip Linus' hand with its fanged beak. Rumor has it that on moonlit nights Linus still runs out into the darkness and jumps, stark naked, into icy water. Of course, he's Finnish and may always have done this. In any case, this is why the Penguin is the Linux Mascot.

Why Penguins?

This email from Linus in response to this very question seems to explain the significance of the Penguin:

Letter goes like this:

Re: Linux LogoLinus Torvalds (torvalds@cs.helsinki.fi)

Sun, 12 May 1996 09:39:19 +0300 (EET DST)

Umm.. You don't have any gap to fill in.

"Linus likes penguins". That's it. There was even a headline on it in some Linux Journal some time ago (I was bitten by a Killer Penguin in Australia - I'm not kidding). Penguins are fun.
As to why use a penguin as a logo? No good reason, really. But a logo doesn't really ave to _mean_ anything - it's the association that counts. And I can think of many worse things than have linux being associated with penguins.

Having a penguin as a logo also gives more freedom to people wanting to use linux-related material: instead of being firmly fixed with a specific logo (the triangle, or just "Linux 2.0" or some other abstract thing), using something like a penguin gives people the chance to make modifications that are still recognizable.

So you can have a real live penguin on a CD cover, for example, and people will get the association. Or you can have a penguin that does something specific (a Penguin writing on wordperfect for the WP Linux CD, whatever - you get the idea).

Compare that to a more abstract logo (like the windows logo - it's not a bad logo in itself). You can't really do anything with a logo like that. It just "is".

Anyway, go to "http://www.isc.tamu.edu/~lewing/linux/ for some nice examples..

Linus

Courtesy:

http://www.sjbaker.org/tux/
http://us5.samba.org/samba/docs/

SAMBA Permission Vs Linux Permission: Who takes precedence

2007-05-19T20:41:00.000+05:30

Few things about Linux and Samba permissions:

1. Linux system permissions take precedence over Samba permissions. For example if a directory does not have Linux write permission, setting samba writeable = Yes , will not allow to write to shared directory / share.

2. The filesystem permission take precedence over Samba permission. For example if filesystem mounted as readonly, setting writeable = Yes will not allow to write to any shared directory or share via samba server.

How do I set permissions to Samba shares? Samba Basic permissions are as follows (configuration file is smb.conf [/etc/samba/smb.conf]):

1. Read only: This parameter controls whether an user has the ability to create or modify files within a share. This is default.

2. Guest ok: Usually this parameter is set to yes, the users will have access to the share withouthaving to enter a password. This can pose security risk.

3. Writeable: Specifies users should have write access to the share.

You can create the share called helpfiles with read only permission

[helpfiles]

path = /usr/share/docs

read only = Yes

You can create the share called salesdoc with write permission

[salesdoc]

path = /home/shared/sales

writeable = Yes

You can also create a list of users to give write access to the share with write list option. For example allow rocky and tony to write to the share called sales:

[salesdoc]

path = /home/shared/sales

write list = rocky tony

You can use following options:
Read list: This option accepts a list of usernames or a group as its value. Users will be given read-only access to the share.

Valid users: You can make a share available to specific users. Usernames or group names can be passed on as its value.

Invalid users: Users or groups listed will be denied access to this share.

Samba mask permission :

It is also possible to specify samba default file creation permission using mask.
create mask: This option is set using an octal value when setting permissions for files. directory mask: Directories must have the execute bit for proper access. Default parameter is 0755.

[salesdoc]

path = /home/shared/sales

write list = rocky syscreate mask = 0775

Courtesy: VIVEK

http://www.cyberciti.biz/tips/how-do-i-set-permissions-to-samba-shares.html

New Samba 4.0 targets Active Directory

2007-05-19T00:26:00.000+05:30

A next-generation test version of the open source Samba file sharing software has been made available, with features emulating Microsoft's Active Directory ID management software. The popular Samba suite is an implementation of Microsoft's SMB (Server Message Block)/CIFS (Common Internet File System) protocol that allows other operating systems to emulate or interoperate with Windows for the purposes of sharing files or printing.

Releasing a new version of the software today in conjunction with a speech on the subject by Australia-based Samba creator Andrew Tridgell at the Linux.conf.au conference in New Zealand, the team behind the software outlined its new features.

"Samba 4 supports the server-side of the Active Directory logon environment used by Windows 2000 and later, so we can do full domain join and domain logon operations with these clients," the group said in a statement on its Web site, noting this feature was "the main emphasis" for the new software.

"Our domain controller implementation contains our own built-in LDAP (Lightweight Directory Access Protocol) server and Kerberos key distribution centre as well as the Samba 3-like logon services provided over CIFS," the statement continued.

The Samba developers noted their implementation of Kerberos correctly dealt with the "infamous Kerberos PAC (Privilege Access Certificate)" -- a data field in the Kerberos authentication protocol which attracted controversy when critics claimed that Microsoft's version tied users into its own version of Kerberos.

Other improvements include the integration of Samba's Web-based administration tool (SWAT), a new scripting interface which allows Javascript programs to interface with Samba's "internals", and new Virtual Filesystem (VFS) features.

Also, "the Samba 4 architecture is based around an LDAP-like database that can use a range of modular backends". "We are aiming for Samba 4 to be a powerful front end to large directories," said the statement.

Courtesy:http://www.zdnet.com.au/

Learning Tutorials: Linux | UNIX | Networking

2007-05-18T23:15:00.000+05:30

Learn Unix in 10 Minutes
http://networking.ringofsaturn.com
networking.ringofsaturn.com/Unix/unixguide.php

Compiling the Linux Kerenel
http://networking.ringofsaturn.com/Unix/linux-kernel.php

How Network Traffic Flows – Getting Started
http://networking.ringofsaturn.com/IP/howtrafficflows.php

What is routing?
http://networking.ringofsaturn.com/IP/Routing.php

IBM ENTRY SAN: DS3000 Series, is a S.A.F.E.R option

2007-05-18T14:45:00.000+05:30

S:Scalable :Start with low investment, later Grow to over 14 Terabytes of capacity
A:Affordable :Excellent Value
F:Flexible: Can attach to System x, BladeCenter and 3rd Party servers. Best for mixed-server vendor enviornment.
E:Easy : DS3000 Storage Manager software makes deployment & installation simple
R:Reliable : IBM quality

Watch Video:
http://youtube.com/watch?v=Kbb7xQACWxw

What is Samba? -Ashwin

2007-05-16T15:11:00.000+05:30

What is Samba?

Samba is an open source software package that mimics a Windows server. Its purpose is to offer an alternative to expensive, unstable Windows servers. Samba can replicate nearly all of Windows server functionality. It appears in the Network Neighborhood like any other Windows machine and functions in the same way. In fact, some servers on your network right now could be running Samba instead of Windows and no one would ever notice.

Samba essentially consists of two or three daemons. A daemon is a UNIX application that runs in the background and provides services. An example of a service is the Apache Web server for which the daemon is called httpd. In the case of Samba there are three daemons, two of which are needed as a minimum.

1. nmbd : Daemon acts as a WINS server service providing DNS-like name-to-IP address translations.

2. smbd : Daemon is the core Samba server service which enables file and printer sharing, network browsing, etc.

winbindd: (3rd Daemon)
This daemon should be started when Samba is a member of a Windows NT4 or ADS domain. It is also needed when Samba has trust relationships with another domain. The winbindd daemon will check the smb.conf file for the presence of the idmap uid and idmap gid parameters. If they are are found, winbindd will use the values specified for for UID and GID allocation. If these parameters are not specified, winbindd will start but it will not be able to allocate UIDs or GIDs.

SAMBA shell script resides in following dir:
/etc/init.d/samba

The main Samba configuration file called smb.conf and is located in this directory:
/etc/smb/samba.conf

Warning: Make sure you backup this file, before making any alterations. Use this command:
cp /etc/samba/smb.conf /etc/samba/org-smb.conf

The smb.conf file supplied with most linux distributions has six sections:

1. [global] - contains many subsections for network-related things such as the domain/workgroup name, WINS, some printing settings, authentication, logging and accounting, etc.
2. [homes] - for file sharing of user home directories
3. [netlogon] - commented out by default, for setting the server to act as a domain controller
4. [printers] - for printer sharing of locally-attached printers
5. [print$] - to set up a share for Windows printer drivers
6. [cdrom] - commented out by default, to optionally share the server's CD-ROM drive

I have only edited following section for my sharing:

[global]
Workgroup = Redhat-SAMBA
Server String = Samba Server
hosts allow = 1.1.1.8
encrpt passwords = yes
smb passwd file = /etc/samba/smbpasswd

[files]
comment = Shared Files
path = /myshare
writeable = yes
Browseable= yes
Valid users=username

Note: I presume , both Windows and Linux box can see/ping each other. Minimum requirement. It is advisable to add the netbios name entry in each other machine.

For Example:
Here is my /etc/samba/lmhosts file
windows machine IP address

And here is my /etc/hosts file:
Linux machine IP address

To configure Samba on your Red Hat Linux system to use encrypted passwords, follow these steps: If someone needs to access a share on your Samba server, they must be both a valid user of the system and a valid Samba user.

Adding Users to a Linux System

To add users to a Linux system, use the following command:

adduser

For example, to add user ashwin to the system, execute the command

adduser ashwin

After adding the user, specify a password for them with the command

passwd

For example to change ashwin password execute

passwd ashwin

Adding Samba Users

To add users to the Samba users list, execute the command

smbpasswd -a

For example, to add ashwin , execute the following

smbpasswd -a ashwin

That's it, now start the SMB service and reload the smb.conf file.

To start smb service:
/etc/rc.d/init.d/smb restart

or

# smb service restart

To reload smb.conf file:
/etc/rc.d/init.d/smb reload

or

# smb service reload

Finaly in Windows Machine:
Open the Windows machine Go to Mynetworkplaces Entire Network Microsoft Windows Network and You should find the "SAMBA" server. You can decide what workgroup name you want to give in the smb.conf file.

Courtesy: Samba: An Alternative to Windows Servers
http://www.mcsr.olemiss.edu/bookshelf/articles/Samba.html
http://samba.org/samba/docs/man/Samba-HOWTO-Collection/install.html

How 2 Setup Linux (network, smb, apache)

2007-05-11T12:15:00.000+05:30

15 years Linux: past and future (video)

2007-05-11T12:09:00.000+05:30

On 21 August 1991, Linus Torvalds first announced the existance of Linux in a posting to a Unix mailing list. This August, Linux will celebrate 16th birthday.

Sun Fire x4500 demonstration:

2007-05-11T11:58:00.001+05:30

Sun Microsystems in July,2006 unveiled three new servers including the Sun Fire X4500: a 4-way AMD Opteron system with up to 24 terabytes of storage. The system's chief architect Andy Bechtolsheim walks us through the system's features.

Hardware-related questions about Complete PC Restore :

2007-05-11T11:17:00.000+05:30

We’ve seen a lot of questions about restoring Complete PC Restore images to different hardware. Here are some answers to the common questions.

Q. Can you restore a Complete PC Backup image to a smaller drive if the amount of space used in the initial backup is smaller than the smaller disk?

A. The backup can be restored only if:

At least the same number of hard drives are present, and
Each disk is at least as big as the disk it replaces.

Here are some examples to illustrate this:

Working examples

During backup
---------------------------------
1x100GB drive
1x100GB drive
1x100GB drive
1x100GB drive,1x200GB drive
1x100GB drive,1x200GB drive

During restore
--------------------------------

1x100GB drive

1x200GB drive

1x200GB drive, 1x80GB drive

1x100GB drive, 1x200GB drive

2x200GB drive, 2x200GB drive

Non-working examples

During backup
----------------------------------------------
1x100GB drive
1x100GB drive
1x100GB drive
1x100GB drive, 1x200GB drive
1x100GB drive, 1x200GB drive
1x100GB drive, 1x200GB drive

During restore

---------------------------------------------

0 drives*

1x80GB drive

1x80GB drive, 1x40GB drive

1x500GB drive

1x500GB drive, 1x160GB drive

1x500GB drive, 1x80GB drive

*possibly due to no drivers loaded in Windows Recovery Environment (RE)

Courtesy: cfsbloggers
http://blogs.technet.com

Practical approach to ISCSI: - My personal views & understanding. - Ashwin

2007-05-06T00:03:00.000+05:30

Is I-SCSI an Software Or Hardware ?

Still confused ? , well the answer is, its in both forms, as explained below.

I-SCSI can be thought as client-server architecture.
A "client" (ie: your system - OS) is an initiator, it initiates requests."
A "server" (ie: your storage device - Disks) is a target.

I-SCSI Software Package includes:
1. ISCSI- Initiator (Free download available)
2. ISCSI- Target (Free download available, NOT all vendors)

A software initiator and Target is just a driver that handles all requests and pairs the network interfaces driver and the SCSI drivers together to make it all work.

Bottom Line: There is no cost involved in using a software initiator and Target (Though some Vendors has price tag for target sofware ) . Disadvantage may be: High CPU usage on Host due to processing of TCP/IP + SCSI Commands.

I-SCSI Hardware Package includes:
1. ISCSI- HBA as Initiator as shown in pic above.
2. ISCSI- HBA as Target as shown in pic above.

Hardware Card is nothign but a ethernet card with a SCSI ASIC on-board to offload all the work (TCP/IP + SCSI processing) from the system CPU.

Note: Each iSCSI HBA adapter has two IP addresses: one for SCSI and one for LAN.With iSCSI HBA, TCP/IP and iSCSI protocol processing may be performed on an embedded processor.

Thank You, views from technical gurus are welcome.

FYI: With due courtesy to following sites.
Reference: (Courtesy:http://www.snwonline.com/implement/isci_feasible_04-15-2002.asp)Reference: (Courtesy:http://www.cuddletech.com/articles/iscsi/index.html)
Reference(Courtesy:http://www03.ibm.com/systems/i/
bladecenter/flash/iscsi_systemx_install.swf)

I-SCSI network , really cool concept. It has scalability and capability.-Ashwin

2007-05-03T17:30:00.000+05:30

Today i tested the I-SCSI theory which i have been reading and writing about since last week, I installed the initiator on my production Windows XP machine and the target on my Test Server running Windows 2003 Ent server. I must tell you it worked out-of-box and this is what i call customers delight.

Theory: iSCSI Protocol Concepts and Implementation
http://www.cisco.com/en/US/products/hw/ps4159/ps2160/
products_white_paper09186a00800a90e4.shtml

Installation Sofware:

I-SCSI Initiator:
You can get the iSCSI Initiator from the Microsoft download website:

Courtesy:
http://www.microsoft.com/downloads/details.aspx?familyid
=12CB3C1A-15D6-4585-B385-BEFD1319F825&displaylang=en

I-SCSI Target:
Download FREE StarWind iSCSI Target evaluation version 3.2.2 from following link:

Courtesy:
http://www.rocketdivision.com/download_starwind.html

You can even watch a video on I-SCSI setup:mms://wm.microsoft.com/ms/inetpub/keithcombs/iSCSI.wmv for the iSCSI demo.

Courtesy: Keith Combs
http://blogs.technet.com/keithcombs

Four Stages to implimenting iSCSI :Courtesy:
http://www.iscsi-storage.com/iscsi_stages.htm

Microsoft Storage Technologies - iSCSI
http://www.microsoft.com/windowsserver2003
/technologies/storage/iscsi/default.mspx

what the hell is i-SCSI ? -Ashwin

2007-05-02T11:08:00.000+05:30

what the hell is i-SCSI ?

When i first heard this term two years back , i thought it is "Ice-SCSI", it sounded like that, and for no reason i felt it is something complicated technology and my assumption was quite natural and i guess every individual have certain assumption on the way technical term sounds, though my theory of assumption is ridiculous but let me tell you its not complicated.

Coming back to "What is I-SCSI" ? , let me try to explain in the less complicated manner.

I-stands for Internet and SCSI as you know stands for Small Computer System Interface. SCSI deals in "Blocks" and Internet deals in "Packet" i.e IP Packet. Here both SCSI and Ethernet technology work together to perform SCSI Data transfers over TCP/IP networks.

It basically allows the block storage SCSI commands to be carried by the standard TCP/IP protocols over the Ethernet wire.

Until recently, Ethernet was too slow to compare to the performance of direct attach storage. With the advent of 1 Gigabit and 10 Gigabit Ethernet, an Ethernet network is now fast enough to use for storage applications.

Technically, this is how it works:
Basically, iSCSI is composed of "initiators" and "targets" that will be used at both ends of the Ethernet wire. The iSCSI initiator connects the computer that initiates the request for data stored on the disk with the Ethernet wire. The iSCSI target connects the Ethernet wire with the storage device, whether it be an array of disks or perhaps a tape device. The initiator encapsulates the SCSI commands and data, so that they can be sent over TCP/IP; and, the target extracts the commands and data at the storage device end of the wire.

From end-user point of view, this is how it works:
When an end user or application sends a request for data, the operating system creates the appropriate SCSI commands, which then go through encapsulation and, in some circumstances, encryption. A packet header is added to the resulting IP packets, and the data is transmitted, typically over an Ethernet connection. When a packet is received, it is decrypted and disassembled, separating the SCSI commands and the data request. The SCSI commands are sent on to the SCSI controller, and from there to the storage device. Because iSCSI is bi-directional, the protocol can also be used to return data in response to the original request.

IBM is already shipping a native iSCSI IP storage system, the IBM TotalStorage IP Storage 200i. Analysts say other companies will speed products to market, once the IETF formalizes the standard. Since 2001 , other companies have also introduced ISCSI storage products.

Wondering how the Internet really works? Learn TCP/IP in most enjoyable way.

2007-04-29T12:45:00.000+05:30

Courtesy:warriorsofthe.net ; This is how we need to teach technology in school and colleges, I appreciate the worriorsofthe.net team for brining such an outstanding video teaching the basics of TCP/IP in such a enjoyable manner, we need to take leaf out of it and have similar practice in our school and colleges, i think it is the best way to learn technology , unlike schools and colleges in our contry where we are stuffed with books and books and degrees by the time we exit out of the education system.

A must watch for every IT networking and support engineers....

Download the movie from :
http://warriorsofthe.net/movie.html

OSI Model Training Tutorial (1 of 3) : Networking for beginners.

2007-04-26T23:31:00.000+05:30

Training Tutorial has three videos explaining all the layers of OSI model.
1.OSI Model Training Tutorial (1 of 3)
2.OSI Model Training Tutorial (2 of 3)
3.OSI Model Training Tutorial (3 of 3)

http://www.youtube.com/watch?v=vAY9uD1tb7U (2 of 3)
http://www.youtube.com/watch?v=ds7dWnGkN38 (3 of 3)

Network Attached Storage: NAS Device from VANTEC.

2007-04-26T23:05:00.000+05:30

You can use this device as an another hardrive, yet configure it as separete HTTP Or FTP server for network sharing. You can keep the box live 24 x7 and dump all the files that you want to share with your friends and business contacts. Isn't it cool!!!!

eCDN (enterprise content delivery network)

2007-04-26T20:51:00.000+05:30

An application of content-delivery network techniques to a closed enterprise network or intranet. A typical eCDN combines caching, intelligent network devices and rules-based management to reduce latency in document delivery. Mainly used today for Web data (i.e., HTML pages), some predict eCDNs could eventually be used to manage other types of data, including e-mail, streaming media and information stored in legacy servers and mainframes.

Overview of Enterprise Storage : For all the storage techies.

2007-04-26T20:05:00.000+05:30

Types of Enterprise Storage:
1. Direct Attached Storage (DAS).
2. Network Attached Storage (NAS).
3. Storage Area Network (SAN).

Storage Networking Training Video: SAN

2007-04-26T19:57:00.000+05:30

A must for any fresher, Or even a techy to go through his video, it shows how data can be managed with the help of SAN. I will add more such video for amatuers so that they learn the technology with fun.

Learning Linux : Class room update.

2007-04-26T19:53:00.000+05:30

Today we are going to share another cool command which runs on UNIN / Linux etc.

Cool Computer Program: Engineers you will love it.

2007-04-26T19:48:00.000+05:30

Great computer program which simulates directly on your screen, just like you do it on piece of paper.

Networking and Storage - How much you know ?

2007-04-26T00:15:00.000+05:30

In this video, we asked people living in and around silicon valley, some simple questions to test how much they know about the technology and companies that is shaping the world around us.

Don't switch to Linux, migrate there :

2007-04-21T13:50:00.000+05:30

Ask yourself, "what are your needs" . Keep your Windows setup for whatever you need it for, and use the new Linux setup for only the things you've learned to do with it. That way there's no awful period when you're stuck with nothing until you figure out the new stuff.

It is important to remember that Linux and Windows are both operating systems and, as such, don't actually provide any significant functionality of themselves. Rather they provide an environment in which applications, that provide the functionality you require, can run. So the question to consider is does the operating system you are considering support the applications that you need? In general, most of the Linux distributions will support applications that provide equivalent functionality to their Windows counterparts. But mostly they are not the same applications, so there will be a learning curve.

How realistic is it for the average Windows user to install and use a Linux-based OS ?

2007-04-21T13:48:00.000+05:30

The first question to ask before getting new hardware or software is always "what are your needs?" Then what are your resources, and finally, what is available?

Most home users surf the Web, do e-mail, take and share digital pictures (well, you will), and trade and print documents with your friends. An open-source operating system does those things. It's safer on the Internet, because it doesn't get viruses.

There's one place open-source falls down, and that's running the very *cheapest* modems, printers, and cameras. If you've still got that ink-jet printer or all-in-one that came "free" with your mail-order Dell, chances are you'd have to replace it with a better model that has Linux device drivers. The same goes for most "software" modems, and Web cams. The good news is your Linux system will come with drivers for the mainstream and high-end devices. You should check one of the Linux compatibility sites or at least ask in a Linux forum before buying hardware that you expect to use with Linux. (linmodems.org, linuxprinting.org, gphoto.org and click on "800 cameras.") If that kind of thing is a show-stopper for you, you're stuck with Windows or Macintosh.

Do you take work home? (I guess not, or you would have had to ditch Windows-98 by now.) Do you run specialized software for stock trading or architectural design? Chances are it only runs on Windows. Do you have a favorite video game? You probably need Windows to launch it.

What are your resources? Can you afford to put more memory in your PC? Replace your printer? Replace a worn out or too-slow CD drive? Can you take a year to make this transition or do you need to make a fully functional office workstation in the next half hour?

Desktop environments for Linux:

2007-04-21T13:45:00.000+05:30

There are two main desktop environments for Linux, Gnome and KDE. Try them both and see what suits you best. I prefer KDE but that's a personal choice again. There is a project under way to combine the best of each of these two environments into a single universal version.

As far as applications go, you'll need an office system - OpenOffice.org is probably closest to the Microsoft Office you are used to (except for the macros) but there are others. I like KOffice but I got into it before OpenOffice.org was available. All the Linux distributions provide a web browser - Konqueror is quite close to Internet Explorer and Windows Explorer - or you can use any of the open source browsers, Firefox, Opera, Netscape, etc. Kmail is a lightweight email client but again, any of your preferred open source clients have Linux equivalents, Thunderbird, Opera mail, etc. If you work with a lot of digital images, you will want to get to know The GIMP - it has all the functionality of Adobe's Photoshop without the hundreds of dollars price tag! Like Photoshop, it isn't the most user friendly application but as you learn to use its power, that's a small penalty to pay.

Security on Linux systems is in a different league to Windows - it was always designed as a multi-user networked system, unlike Windows single user standalone desktop origins. All Linux systems have an inbuilt two way firewall that you can configure to your own specific requirements. There have been very few viruses targeting Linux but as its popularity increases, that will undoubtedly grow, though that said, it is much harder to break Linux security. Whether you should include an anti-virus application is a matter of heated debate (which I won't encourage here) but what harm can it do?

The beauty of Linux is that you can start simply, use the GUI, never even see a command line unless you want to. But as you get to know it and grow with it, you can branch out into the more powerful features as you need them.

Should you get rid of Windows XP altogether? My advice would be no, at least to begin with. As you explore Linux, you may come across an application you use that you can't find a Linux equivalent for, so having a Windows system to revert to is a good safety net. You have a licence for it anyway, so apart from the disk space, it's no loss to keep it until you have stopped using it altogether. I still use both for client compatibility, which is another reason you might want to keep XP,

I hope that's given you a few ideas to think about - you've nothing to lose - it's almost all free - as the SuSE Linux installer used to say - Have fun! Good luck.

The power of competition: - Ashwin

2007-04-20T00:14:00.000+05:30

This is perhaps the greatest power in the world, the so called "Power of competition".Let us scruitnized the word competition which is not only driving the business but everything around us in the 21st century.

Competition: If we look at the world around us, we can easily feel the puslse of competition, whether it is an Athlete striving for Gold in Olympics, a young graduate in opening of a new job , Or a student aiming to top the class and last but not the least , the ever concious common men and women competing to raise the social-standing in the soceity, so the competition is just about everywhere, i don't think any one of us can escape.

Competition, is always healty and in the interest of the betterment of the contry as long as it is in the right spirit, by healthy i mean equal opportunity to all the players who is in race to compete for the best.

Unhealthy competition means pulling one another's leg to win the race, conspiring to erase the opponent, attacking the opposition in a unethical way etc etc. In sports, if we take an example of unhealthy competition we would come across stories of atheletes taking unfair means such as drugs to win the Gold, Hence the spirit of competition taking the ugly shape and that's realy sad.

Unhealthy competition could mean parents pressurising their kids to do what they would like them to, irrespective of what they like to do themselves, this is really sad and not the true side of the competition.

On the positive side, competition has and always paid a great dividens to the people who have embraced it in a right manner, those who have honestly strived and are still striving to give their best without compromising on principles are trully appreciable.

Finaly, competition has direct link with Quality. it is a proven fact that, competition has given rise to "Superior Quality", which has infact benefited the customers with wide range of Quality products and services.

Due to competition, customers have become the KING, every company is aiming to snatch customers from each other, and in a process given the remote control to "common man" the customers , Now we can choose the product we want, which ends the ERA of "MONOPOLY".

Fact reamains, No competition------No Growth.

Symantec Backup Exec™ System Recovery :(formerly Symantec LiveState™ Recovery)

2007-04-19T02:07:00.000+05:30

Symantec Backup Exec System Recovery (formerly LiveState Recovery) combines the speed and reliability of disk-based, bare-metal Windows® system recovery with revolutionary technologies for hardware-independent restoration and lights-out operation. The result is unparalleled freedomto restore systems anytime, from anywhere, to virtually any device.

For details check out this pdf:
http://a248.e.akamai.net/f/248/5462/2h/www.symantecstore.com/v2.0-img/page-builder/Symantec/images/10702265_BUESR_ds.pdf

See the SAN Storage Setup Guide by HP: Build your company's first SAN

2007-04-19T02:03:00.000+05:30

Note: Follow the "Download a PDF version" link at right to download a PDF version of this guide that includes additional product information and a tape backup QA.

http://www.hp.com/sbso/productivity/howto/san/index.html

Perplexed by the word Storage Area Network (SAN) or just don't know how to implement a SAN in your company ? Here's a great guide from HP that tries to make that process clearer.You might also want to check out the new HP StorageWorks portfolio that would help customers consolidate their storage environments.

Digital information is a critical component of business today. It not only continuously grows in volume, but many businesses require that it is available around the clock. Inability to access your information—even to perform a system backup—is no longer an option. Add a shrinking IT budget to these realities, and you're presented with a real challenge. How do you provide efficient storage, management, and availability of your data? The solution can be found in a highly flexible, intelligent, and easy-to-manage storage solution that is also cost-effective: the SAN (Storage Area Network).

As an IT manager, you are faced with critical choices. Do you restrict the type and quantity of information each user is allowed to store and access, potentially limiting their capability to perform their daily activities? Or, do you continue to invest in individual disk drive after disk drive that you connect exclusively to a single server in a Direct Attached Storage (DAS) model that drains man-hours with management and monitoring requirements?

Recommended PORT consideration for Firewall/TCP Filtered environment:

2007-04-17T01:00:00.000+05:30

When performing remote backups through a firewall, one should select a specific range under Network & Firewall defaults dialog box in the Backup Exec console and open the exact range on the Firewall/TCP Filtering.

Note: According to IANA (INTERNET ASSIGNED NUMBERS AUTHORITY),Ports which we think is Dynamic and Free are not TRUE, Infact when we go through the List of ports given by IANA authority we will find that most ports which we assign are either well known ports OR registered ports and therefore when we specify them in Backup Exec console (Under Network & Firewall) option it does not follow the rule and often get rejected/Refused by the remote server.

According to IANA :

http://www.iana.org/assignments/port-numbers

PORT NUMBERS =(Last update 2006-11-17)
The port numbers are divided into three ranges:
1.The Well Known Ports.
2.The Registered Ports.
3.The Dynamic and/or Private Ports.

The Well Known Ports are those from 0 through 1023.
The Registered Ports are those from 1024 through 49151
The Dynamic and/or Private Ports are those from 49152 through 65535 (Here we need to search for unassigned ports)

As we can see port between 1024 and 49151 is registered and therefore even if we specify these range on the Backup Exec(under tools--options--network & firewall) and similar range on the remote server Firewall/TCP Filerting it may not backup or "refuse to communicate" as seen in the SGMON error.

Backup Exec error Traced in SGMON:
bengine: [3044] 09/12/05 11:53:47 TF_InitMediaServerReverseConnection: Data Connection: Failed to connect to remote address 170.140.236.128:3189,system error message: "No connection could be made because the target machine actively refused it".
This is an clear example of ports been blocked on the TCPFilterting/Firewall except for Port 10000 which is usually the only port opened by network administrator(s) which is used for control connection.

Solution:
To overcome this problem, its recommended to specify maximum FREE (UNASSINGED Dynamic Port) range available and stated by IANA and as per the IANA information it looks like the maximum range available is :5204-5221 which is about 17 ports. Its up to the system administrator to open all the "17" ports or just assign "10" ports. You may refer to IANA website to refer other range.

Specify the range as shown below:
Enable Remote Agent TCP dynamic port range:
5204- 5221

Unless you specify range, Backup Exec uses full range of dynamic ports available which may not work in Firewall/TCP Filtered domain/Environment.

Note: Its recommended to keep range of ports opened instead of just one because being a dynamic port it can be engaged by any other application can cause data connection issues, Therefore atleast keep "10-25" ports opened on the Remote system.

For Ex-
NUMBER OF SIMULTANIOUS BACKUPS =5
NUMBER OF PORTS REQUIRED FOR DATA = 5

Its just an example but make sure at least "10-25" ports opened on remote system Firewall/TCP Filters.

Control connection is always established on port 10000 and once the connection is established the port is FREE to listen to another connection from media server, but the subsequent data backups will need extra port for data pass-through because the previous port is engaged by the first backup job.

Storage Jobs - Storage Area Network or SAN jobs :

2007-04-12T16:49:00.000+05:30

For Storage , Networking, Unix, Volume Manager Interview Questions & Answers please read the following blog. Interview questions on SCSI, HBA ,RAID , storage device types.

Catch this blog:
http://storage-jobs.blogspot.com/

The Difference Between FTP and HTTP :

2007-04-12T00:48:00.000+05:30

File Transfer Protocol, or FTP, is a protocol used to upload files from a workstation to a FTP server or download files from a FTP server to a workstation. It is the way that files get transferred from one device to another in order for the files to be available on the Internet. When ftp appears in a URL it means that the user is connecting to a file server and not a Web server and that some form of file transfer is going to take place. Most FTP servers require the user to log on to the server in order to transfer files.

URL starts with:
ftp://

In contrast, Hyper Text Transfer Protocol, or HTTP, is a protocol used to transfer files from a Web server onto a browser in order to view a Web page that is on the Internet. Unlike FTP, where entire files are transferred from one device to another and copied into memory, HTTP only transfers the contents of a web page into a browser for viewing. FTP is a two-way system as files are transferred back and forth between server and workstation. HTTP is a one-way system as files are transported only from the server onto the workstation's browser. When http appears in a URL it means that the user is connecting to a Web server and not a file server. The files are transferred but not downloaded, therefore not copied into the memory of the receiving device.

URL starts with:
http://

Connecting using FTP:
The FTP (File Transfer Protocol) utility program is commonly used for copying files to and from other computers. These computers may be at the same site or at different sites thousands of miles apart. FTP is a general protocol that works on UNIX systems as well as a variety of other (non-UNIX) systems.

For the purposes of this Web page, the local machine refers to the machine you are initially logged into, the one on which you type the ftp command. The remote machine is the other one, the one that is the argument of the ftp command.

Getting Started:
To connect your local machine to the remote machine, type :
# ftp machinename

where machinename is the full machine name of the remote machine, e.g., for.test.purpose.edu. If the name of the machine is unknown, you may type
#ftp machinennumber

Anonymous FTPAt times you may wish to copy files from a remote machine on which you do not have a loginname. This can be done using anonymous FTP.

When the remote machine asks for your loginname, you should type in the word anonymous. Instead of a password, you should enter your own electronic mail address. This allows the remote site to keep records of the anonymous FTP requests.

Once you have been logged in, you are in the anonymous directory for the remote machine. This usually contains a number of public files and directories. Again you should be able to move around in these directories. However, you are only able to copy the files from the remote machine to your own local machine; you are not able to write on the remote machine or to delete any files there.

ftp Learning Links:
Active FTP vs. Passive FTP, a Definitive Explanation
http://slacksite.com/other/ftp.html

For complete FTP commands:
http://www.cs.colostate.edu/helpdocs/ftp.html

What is Needed to Use FTP sFTP :
http://www.uic.edu/depts/accc/network/ftp/vftp.html#h1p02

Commands Used to Transfer Files :
http://www.uic.edu/depts/accc/network/ftp/vftp.html#h1p03

How to clear the Browsing HISTORY and the FORMS such as search queries and your search pattern.

2007-04-09T11:21:00.000+05:30

As you long as you are the sole user of your laptop or desktop machine, its nothing to worry about, but you never know when you will be in a situation when somebody would need your laptop to browse for a minute or whatever time length depending upon what kind of relation or understanding you have with the other person, i always belived its safe to keep your machine in clean state once you have done with your days work Or when someone requests for your machine.

Clearing Browsing link History:
1. Go to Tools Internet Options

2. Under General tab under History Click Clear History.

Clearning Forms (Search History):
1. Go to Tools Internet Options

2. Click on "Content" tab.

3. Click "AutoComplete" under Personal information.

4. Click "Clear Forms".

5. Click "ok".

BRUSH-UP WITH SQL DATABASE : Very Basic

2007-04-08T17:41:00.000+05:30

When a SQL database is created, two or more files are created to support that database. These files are the Primary Data File and the Transaction Log File. Primary Data Files have an extension of ".MDF" and Transaction Log Files have an extension of ".LDF". A database may also have Secondary Data Files, having an ".NDF" extension. (Note: You can actually use any extension for your files but these are recommended for consistency.)

Every database must have a Primary Data File. This file contains the system tables for the database, pointers to any other files used by the database, and can also contain data. Secondary files contain any data that did not fit in the Primary. Databases do not necessarily have a secondary file, but may have one or more. The Transaction Log File contains all of the log information that may be used to recover a database. Each database has a Transaction Log File, though there may be more than one.

File Group is a important segment of the SQL database,

If, you are wondering WHY ? Read below

Imagine you have a database which is about 20 GB and its keeps growing, but there is only two tables that are getting updated frequently.

Then,

Instead of Backing the FULL DATABASE you can just put those tables on the file group and just backup the file group, reason : why should you backup the whole database when only TWO TABLE is getting updated ?

Save Time and Space.

Lets see how to create a File Group

Creating FILE GROUP
1) Open Enterprise Manager.
2) Open your Local instance.
3) Right click on database ---Choose---create NEW.
4) Give a suitable Name---Click ok.
5) Right click on the database that you just created---Choose Properties.
6) From the Menu---Click on File Group TAB.
7) By default you will see Primary FILE GRP, Create a New FILE GRP underneath that and name it as ---SECONDARY.
8) Click on Ok....Secondary File GRP is now created.
9) Right click the database you created this time --click on ---- Data files.
10) Finally, Create a secondary file (.NEFF) and give it a separate path and select SECONDARY under File Group.

Now, go ahead and create tables, these tables will now be listed under secondary file group rather then Primary.

That's it!

Disclaimer: This information is purely my understanding and views.

Error: SMB signing is mandatory and we have disabled

2007-04-05T16:46:00.001+05:30

when attempting to mount a windows machine from a linux machine using following command:
mount -t smbfs //machine/share /root/smb_mnt -o username=administrator,password=mypass

Following error occurs:
cli_negprot: SMB signing is mandatory and we have disabled it.26595: protocol negotiation failed SMB connection failed

Even after editing the "smb.conf" file and setting the option 'client signing = yes' does not resolve issue.

Cause:
Server Message Block (SMB) signing is a security mechanism in the SMB protocol and is also known as security signatures. SMB signing is designed to help improve the security of the SMB protocol. if SMB is disabled on Linux then, make sure its also disabled on Windows machine (Workstation/Server).

For Windows Server :This is due to a security policy in Windows 2003 Server that forces the connections to be encrypted.

Resolution for Windows Workstation:
Go to following registry key on the Windows machine and set it to "0" disable.

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\LanManWorkstation\ParametersValue Name:

EnableSecuritySignature Data Type: REG_DWORD Data: 0 (disable)

Resolution for Windows Server :
If it's a windows 2003 Server then :
Go to Administrative Tools -> Domain Controller Security Policy. Then select Local Policies -> Security Options and find and disable both these policies:
1. Microsoft network server: Digitally sign communications (always)
2. Microsoft network server: Digitally sign communications (if client agrees)
After the changes, just run the command 'gpupdate' to refresh the policy changes you made.

More information read the following MS article
http://support.microsoft.com/kb/887429

Disclaimer: Please peform the steps at your own risk.

Knowledge Management:

2007-04-05T16:25:00.000+05:30

knowledge management is the hottest subject of the day. The question is: what is this activity called knowledge management, and why is it so important to each and every one of us? The following writings, articles, and links offer some emerging perspectives in response to these questions. As you read on, you can determine whether it all makes any sense or not.

Developing a Context:
Like water, this rising tide of data can be viewed as an abundant, vital and necessary resource. With enough preparation, we should be able to tap into that reservoir -- and ride the wave -- by utilizing new ways to channel raw data into meaningful information. That information, in turn, can then become the knowledge that leads to wisdom. Les Alberthal[alb95]

Before attempting to address the question of knowledge management, it's probably appropriate to develop some perspective regarding this stuff called knowledge, which there seems to be such a desire to manage, really is. Consider this observation made by Neil Fleming[fle96] as a basis for thought relating to the following diagram.

A collection of data is not information.
A collection of information is not knowledge.
A collection of knowledge is not wisdom.
A collection of wisdom is not truth.

So, in summary the following associations can reasonably be made:
Information relates to description, definition, or perspective (what, who, when,
where).

Knowledge comprises strategy, practice, method, or approach (how).

Wisdom embodies principle, insight, moral, or archetype (why).

Adapted from Knowledge Management, by Gene Bellinger of Seattle-based http://www.systems-thinking.org/kmgmt/kmgmt.htm

Career in SAN Technical Support:

2007-04-05T00:39:00.000+05:30

Storage Area Network (SAN) is the most happening technology in the storage area space, normally a SAN consultant or administator is responsible for Design, development, day to day administration of Storage environment globally.

Some of the Responsibilities:
Storage Administration - Day-to-day administration of Storage.
Performance Tuning – maintaining predictable performance levels
Design & Architecture - Design and implement reliable , highly available architecture Communication - Develope relationships with other Infrastructure groups.
Documentation – Document critical processes and procedures to ensure consistency and quality. Develop procedures and processes to ensure that Audit and Regulatory requirements are met. Be responsible for Storage Hardware (SAN/NAS/Direct attach) and Storage Software support. Will also be responsible for Backup Hardware and Software support.

Requirements not necessarily hard and fast:
Knowledge of Disk arrays .
Knowledge of Network Appliance NAS Filers Knowledge of Brocade SAN switches Knowledge of Data replication technologies.
Knowledge of Veritas netbackup based Backup environment support.

How to start:
One can join Technical Support centers providing support for Storage and Data backup softwares. Gradually one can gain expertise by working on LIVE SAN enviornment and reading SAN White papers published by various storage companies. Good knowledge of Windows and UNIX flavour is must along with handy knowledge of Networking.

Disclaimer: These are my personal views!

Introduction to storage systems:

2007-04-04T00:40:00.000+05:30

DAS, NAS and SAN differ mainly in where they interface with the network.

There are currently three basic concepts for addressing storage:
1.Direct Attached Storage (DAS),
2.Network Attached Storage (NAS),
3.Storage Area Networks (SAN).

For each definition read the following article.

BIBLE for selecting a Storage-System NAS OR ISCIhttp://www.open-e.com/downloads/WhitePaper/Open-E%20white%20paper%20EN%20(web)2.pdf

What is ISCSI and How iSCSI Works:

2007-04-04T00:36:00.000+05:30

iSCSI stands for internet SCSI, or internet Small Computer Systems Interface. iSCSI is the transmission of SCSI commands and data over IP (Internet Protocol) Networks.

How iSCSI Works:
When an end user or application sends a request, the operating system generates the appropriate SCSI commands and data request, which then go through encapsulation and, if necessary, encryption procedures. A packet header is added before the resulting IP packets are transmitted over an Ethernet connection. When a packet is received, it is decrypted (if it was encrypted before transmission), and disassembled, separating the SCSI commands and request. The SCSI commands are sent on to the SCSI controller, and from there to the SCSI storage device. Because iSCSI is bi-directional, the protocol can also be used to return data in response to the original request.

iSCSI is one of two main approaches to storage data transmission over IP networks; the other method, Fibre Channel over IP (FCIP), translates Fibre Channel control codes and data into IP packets for transmission between geographically distant Fibre Channel SANs. FCIP (also known as Fibre Channel tunneling or storage tunneling) can only be used in conjunction with Fibre Channel technology; in comparison, iSCSI can run over existing Ethernet networks. A number of vendors, including Cisco, IBM, and Nishan have introduced iSCSI-based products (such as switches and routers).

ISCI DIAGRAM:
http://www.digit-life.com/articles2/iscsi/
http://www.iscsi-storage.com/iscsi_stages.htm

Introduction: Storage Area Networks (SAN) :

2007-04-04T00:21:00.000+05:30

To appreciate what a Storage Area Network (SAN) is, we need to understand why SANs came into being. Storage Area Networking has evolved as part of an ongoing effort to find more efficient methods of transporting large blocks of data and the need to share storage resources in various one-to-many models versus the historic server-bound Small Computer System Interface (SCSI) method of storage connection and data transport. As the requirements to share storage resources have increased, in many cases, this SCSI connection model no longer meets the requirements of today's 7x24x365, high data throughput enterprises.

For more details please read thefollowingartile:
http://www.veritas.com/van/articles/2958.jsp#1

SAMBA for NEWBIES...

2007-04-03T11:50:00.000+05:30

Samba is a suite of applications and daemon processes used on Unix-Like machines primarily for communicating with windows machines for sharing filespace and printers.

Samba is based upon SMB (Server Message Block) protocol which describes rules for communication among various machines on a network(for sharing filespace and printers).
Samba's flexibility and functionality are unmatched.

Apart from sharing file space and printers, it offers some more services like:
1. It can act as a Local Browse Master for a Workgroup. Supports domain logon and logon scripts. Supports browsing on other subnetsand also supports replication of Browse list across subnet boundaries.

2. It supports a 'Shared User Database' with all the servers in adomain sharing a distributed NIS or kerberos authentication database.

3. It can act as a WINS server.

4. It supports SMB password encryption scheme.

5. It can be turned into a Fax Server.

6. It can take backup of PCs directly to a tape.

Sharing filespace and printers using Samba. This can be branched into sharing your filespace and printers with others and sharing others filespace and printers with yours.

Sharing your filespace and printers with others:
This is accomplished in terms of services (shares in windows). The concept is simply that your machine offers services to other machines when it lets them read from/write to your drive or when it lets others print on your printer. Services are created by configuring/etc/smb.conf (In fact, smb.conf is the backbone of Samba Suite). Samba offers so much flexibility in making the services that it can bereal fun for a creative mind. This is accomplished by the followingcomponents of Samba suite....

smbdsmbd
is a daemon process that plays key role in providingservices. It listens to the service requests from other machines and responds as specified in /etc/smb.conf (got the importance of this file? ;-)

nmbd
is a daemon process that understands and replies tonetbios name service requests. Whenever its own name (themachine it's running on) is specified, it responds with the IPaddress of the machine it's running on.

smb.conf
This is the configuration file for Samba. All daemon processesof Samba suite read this file which makes it extremely important. I advise you to go through man pages and how-to before you sit down to edit this file. If you don't feel like doing it, I have made an attempt of writing a generic file that should satisfy your needs. You can use it but the condition is that you will have to tell me how bad it is so that others find it a little less bad.

testparm
Once smb.conf is edited to meet your requirements, you have to check it's validity. Here test parm comes for your rescue. It can point out most of the blunders that your smb.conf is likely to cause test prns .

This one points out printing related blunders.

Sharing others filespace and printers:
This is accomplished by a host of commands...

smbclient
smbclient lets you inquire about the services a machine offers.All you have to do is smbclient -L hostname and it lists allthe services of hostname. If you want to browse through aservice, just do smbclient \hostservice. It will give youan ftp like interface.

smbmount
Call it mapping hostservice on drive U:!! You need to accesssome services quite frequently. smbclient is good for quickbrowsing but not feasible in such a case. So, here comessmbmount. It lets you mount hostservice on a directory justthe way you mount any filesystem. Just do smbmount//host/service /path_to_mount_point and it's done. Access thefiles/printers just as they are attached to your machine!

smbumount Well, it's obvious!! You may want to unmount the filesy stem once you are through with your job.

To umount:
smbumount/path_to_mount_point and ....

nmblookup :It finds the IP Address of a machine given it's netbios name(the name by which a machine appears in Network Neighborhood).

LinNeighborhood application: It up. It's a do-all application witha nice GUI for Samba. A pretty good substitute of the abovefour commands if you find command line a little messy!!

what is Proprietary Operating System:

2007-03-18T23:32:00.000+05:30

Computer operating system that functions on only one type of computer. Proprietary operating systems limit the ability of Software applications to run on other systems and also limit the market for any Application Software.

Data ONTAP is a proprietary operating system developed by Network Appliance; it is not based on the Windows OS. Consequently, the current Data ONTAP operating system requires additional rights assigned to the user or to the precreated device object when an administrator or administrator equivalent account is not used. Once the computer object has successfully joined the Active Directory domain, the user account credentials will no longer be used and are not stored in any way in the OS. They are used only to allow the N series storage system to become an active member of Active Directory and to write standard properties to the object during the join process.

Setting up CIFS shares and joining the ActiveDirectory
http://www.techworld.com/applications/whitepapers/index.cfm?whitepaperid=3276

Data ONTAP by Network Appliance :

2007-03-18T23:31:00.000+05:30

NetApp's proprietary OS is called Data ONTAP. Due to licensing deals with Microsoft, however, NetApp is compatible with Windows-based NAS appliances. This allows you to utilize a non-Windows device that interoperates with Windows. Another big plus of Data ONTAP is that it was created specifically for NAS applications and offers the greatest range of high-end features such as advanced mirroring and snapshots. You can use Data ONTAP, for example, for hundreds of data snapshots and point-in-time copies every hour if you require it.

NetApp has established a common architecture across all products based on Data ONTAP and its WAFL (write anywhere file layout) file system. These two elements underlie all its platforms and are a big reason that NetApp dominates in the primary storage part of the NAS landscape. And that's the whole point — NAS was designed to simplify storage management compared to traditional SANs.

"With NAS, the FC part is disguised so a lot less is required of the storage administrator," said Karthik Kannan, director of technology and strategy at NetApp.

But complexity is a relative concept. Compared to some Snap and Windows gear some NetApp filers are quite complex. But as new versions of the OS are released, greater simplification is apparent. The newest edition, Data ONTAP 7G (Grid), adds dynamic virtualization and removes some of the administration from disk configuration at the physical level. This means more time managing data as opposed to managing systems and disks.

"Administrators no longer have to worry about how many disks are attached to a volume and program for backups, and so on," said Kannan.

Version 7G is just the start of NetApp's grid vision. Its acquisition of Spinnaker Networks last year was part of the plan to move into enterprise grid computing. That vision will come into being over the next 12 to 24 months.

GuardianOS from Snap Appliance :

2007-03-18T23:30:00.000+05:30

GuardianOS by Snap is particularly strong in the workgroup and departmental markets. Now that it has been acquired by Adaptec, there are signs that it is moving into larger enterprise environments. Newer appliances, for example scale up beyond 29 TB.

GuardianOS is now up to version 3.1. This latest version adds iSCSI support, block-based services, some dynamic provisioning capabilities and the ability to expand an iSCSI LUN on the fly. Another feature is Snap EDR – enterprise data replication. This is replication and aggregation software that enables remote backups and data transfer over a WAN.
According to Steven Rogers, director of technical marketing for Adaptec's Snap Appliance division, Guardian OS is a more streamlined and resilient NAS OS than Windows or Data ONTAP.

Microsoft Windows Storage Server 2003 :

2007-03-18T23:25:00.000+05:30

According to IDC, NAS appliances running the Microsoft operating system are expected to account for about half of all appliances in the market by the end of 2004. They offer interoperability with Windows environments and can scale from one TB to over 60 TB. Windows Storage Server 2003 is now the central operating system of NAS appliances from a variety of vendors such as HP, EMC and Dell. In addition, the OS is readily available to entry-level customers, and applications for backup, security and management can be acquired from any vendor.

Microsoft has made major changes between the 2000 and 2003 versions and is clearly intent on capturing market share. On the downside, however, some criticize Windows Storage Server as being little more than a server with a browser console. Further, security concerns continue to plague the Windows OS. Due to its ubiquity, it is a magnet for hackers. Thus when security of data is a factor, GuardianOS and NetApp come out ahead. Data ONTAP, in fact, is designed with security in mind. The microkernel of the OS contains all the key features required for backup, replication, WORM etc. With all the software embedded into it, there is no need to load additional software modules that could compromise security. "Windows comes with traditional bugs and flaws," said Kannan. "Data ONTAP's code is tightly compiled for storage so there is no place for a script to execute."

http://www.netapp.com/go/techontap/
matl/sample/0206tot_monthlytool.html

iptables firewall

2007-03-15T12:43:00.000+05:30

The iptables firewall feature also referred to as netfilter is the default firewall software when you install Red Hat Linux 8.0 and 9.0. This firewall can be configured to block ports and thus disallow TCP traffic to and from the Backup Exec server. The Backup Exec Unix Agent on the Linux server/workstation broadcasts every 30 seconds by default to port 6101 on the backup server and listens on TCP port 8192 on the Linux system. Port 8192 must be opened on the Linux server/workstation to allow backup traffic to flow to and from the Backup Exec Unix/Linux Agent.

To determine if iptables is installed,Type:
rpm -qa iptables

To view the currently loaded iptables rules in the kernel, type:
iptables -L

To append a rule to the current rules that allows incoming TCP packets with a source of the media server's IP address to any TCP port on the Linux server/workstation, type:
iptables -A INPUT -p tcp -m tcp -s -j ACCEPT

For a more secure firewall setting that appends a rule to allow TCP packets from the media server through port 8192 on the Linux workstation/server, type:
iptables -A INPUT -p tcp -m tcp -s -d --dport 8192 -j ACCEPT

Can Backup Exec for Windows Servers encrypt data on media?

2007-03-15T12:22:00.001+05:30

Backup Exec (tm) does not encrypt data on media. Backup Exec can only password protect media. If the password is set, then it is required when you catalog or restore media. Information contained on media cannot be read without the correct password.

Note: Password protected media can be "erased" without providing the password.

How to enable ARCHIVELOG mode in Oracle 10g (10.1)..

2007-03-14T00:08:00.000+05:30

Starting with Oracle Database 10g release 10.1, the LOG_ARCHIVE_START initialization parameter has been deprecated. Archiving is now automatically started when the database is placed in ARCHIVELOG mode.

To enable ARCHIVELOG mode in Oracle 10g (10.1):
http://support.veritas.com/docs/266835

Recommended PORT consideration for Firewall/TCP Filtered environment:

2007-03-14T00:01:00.000+05:30

Funny Video, i bet u go mad: NTU Student survey - Funny comments

2007-03-05T19:08:00.000+05:30

http://www.youtube.com/watch?v=QOqXlbWf9Io

Network Data Management Protocol (NDMP/10000)...

2007-03-04T23:44:00.000+05:30

NDMP is an acronym for Network Data Management Protocol, which is an open standard protocol for enterprise-wide backups of heterogeneous network-attached storage. NDMP is an Internet-Draft standard that uses port 10000 by default.

For more details on NDMP Protocol please see the following site:

http://www.ndmp.org.

Architectural Model:
The architecture follows a client-server model and the backup software is considered to be a client to the NDMP server. For every connection between the client and the NDMP host, there is a virtual state machine on the NDMP host that is controlled using NDMP. This virtual state machine is referred to as the NDMP server.

Currently an NDMP server can be thought of providing two services:

A DATA server - This service either reads from disk and produces an NDMP data stream (in a specified format) or reads an NDMP data stream and writes to disk, depending upon whether a backup or restore is taking place.

A TAPE server - This service either reads an NDMP data stream and writes it to tape or reads from tape and writes an NDMP data stream, depending upon whether a backup or restore is taking place. All tape-handling functions, such as split-image issues, are dealt with by this service.

NDMP Filers (NAS):

DMP Filers, or NAS devices, reside on the network with the primary purpose of providing file services. NAS devices that use standard operating systems (for example, Windows-powered NAS devices) support the installation of backup agents, and can therefore be backed up like any other file server. However, some NAS devices use a custom operating system that does not support third party backup agents. A standard backup interface for NAS devices exists in the form of the network data management protocol (NDMP), which is a backup standard for NAS devices that do not support installation of a backup agent.

NDMP - Direct Attached:(Shown above in Figure)
In the direct-attached or local model, the backup server uses NDMP over the LAN to instruct the filer to start the backup. The filer then sends the data contained in the backup to a tape device attached directly to the filer via Fibre Channel or SCSI. During the backup, information about files and directories written to tape is transferred via NDMP over the LAN to the backup server where it is maintained in an index. For a restore operation, the backup server uses NDMP over the LAN to instruct the filer to start restoring files. Data is read from the filer's locally attached tape device and stored by the filer. During backup and restore, the backup server does not ever receive the actual data being written or read from tape. As a result, this model is commonly referred to as "LAN-free" backup.

NDMP - Filer to Filer (3-way): (Shown above in Figure)
In the filer-to-filer model, often referred to as three-way, the backup server uses NDMP over the LAN to instruct filer A to start backing up data to tape devices attached to filer B via either the same network or a private backup network. During the backup, information about files and directories written to tape is transferred from filer A via NDMP over the LAN to the backup server, where it is maintained in an index.

This is known as 3-way backup, since typically 3 hosts are involved.
The host running the NDMP client (1).

The host running the NDMP DATA server (2).

The host running the NDMP TAPE server (3).

RPM Overview ............

2007-03-04T23:37:00.000+05:30

FREE RPM Downloads:
http://rpm.pbone.net/index.php3/stat/3/srodzaj/1/search/compat-gcc

For more details on RPM commands one can refer to following pdf file:http://home.frognet.net/~aalug/docs/rpm.pdf

The RPM Package Manager (RPM) is a powerful command line driven package management system capable of installing, uninstalling, verifying, querying, and updating computer software packages. Each software package consists of an archive of files along with information about the package like its version, a description, and the like. There is also a related API ("Application Program Interface"), permitting advanced developers to bypass 'shelling out' to a command line, and to manage such transactions from within a native coding language. RPM has become the defacto format for LSB compliant distributions.

Basic RPM Commands:
1. -U Update or install the chosen package. This can be done via http or ftp in addition to using local files.
2. -i Install the selected package, allows for multiple versions.
3. -e Remove. This allows you to remove the packages you specify.
4. -v Verbose. Print out more information than usual.
5. -F Freshen. This is similar to -U but will only work on if an earlier version of the package is already installed.
6. -h Hash. This makes rpm pretty when you install packages, and gives you a progress bar.
7. -qa Query all. This allows you to query for every package installed on the system. You can limit the search by giving it a value like rpm -qa "send*".
8. -ql lists the files associated with a package.
9. -qg lists all installed packages in a specific group, for example "System Environment/Shells".
10. -qi lists the spec file header for the given package. This is one of the things that makes rpm useful for automation.

What is "NAMED PIPES" in Unix\LINUX..

2007-03-04T23:22:00.000+05:30

Unix\LINUx supports a special form of pipes known as "named pipes". Very simply, a named pipe is an entry on the disk that looks like a file to the programs that write and read it, but it really doesn't contain any data. It helps connecting the output of one program to another without using the pipe character. A named pipe special file is recognizable by the file type character:

p as in prw-rw---- mypipe

1. Determine potential pipe files, On the Unix or Linux console type the following command:

ls -l

2. Look for anything with a "p" in the first column of the permissions metadata. This indicates a pipe type resource as shown in Figure above..

NOTE: It is recommended to Exclude all pipe type targets during Backup process.

NDMP port 10000 is in use by another application...

2007-03-04T13:33:00.000+05:30

Certain Backup vendors are NDMP compatible and they require NDMP port to be free on PORT-10000, sometimes its used by other applications and could cause the Backup failure.

Resolution:
To resolve the issue, it is required to determine the application/service which is using port 10000, and then either free the port or change the NDMP port on the <>\etc\services file and also on the Bakup as well as Agents server. Its most recommended to FREE the ndmp 10000 port.

Follow the steps given below to determine the port usage:

1. On the RedHat Linux system, open the terminal/command line prompt and type the command given below.

Note: There are number of different commands to check the port status. Choose the command you are most comfortable with. This is what i use, for details on basic linux commands see the links on the right.

lsof -i tcp:10000

The figure above shows that port 10000 is listening for the process ID 17923.

The next step is to determine which application is using this process.

2. To determine the application using a given process, type the command shown below.

ps -ax grep 17923

The figure above is showing that an application called "Webmin" is using NDMP port 10000. The Administrator will need to either free the port or change the NDMP port number to be used by Backup Software.

Note: It is recommended to FREE the port instead of changing the NDMP port to be used by Backup Software, because if you opt to change the NDMP port then this change must be made not only to the Backup Server but too all the agents server.

What is Webmin:
Webmin is a web-based interface for system administration for Unix. Using any browser that supports tables and forms (and Java for the File Manager module), you can setup user accounts, Apache, DNS, file sharing and so on. Webmin consists of a simple web server, and a number of CGI programs which directly update system files like /etc/inetd.conf and /etc/passwd.
Webmin by default uses the port 10000 when installed.

http://localhost:10000/

Backup fails while backing up SNAP/NAS/Netapp servers:

2007-03-04T13:27:00.000+05:30

This could occur if the Backup agent is not ndmp compatible.

1. To check the NDMP daemon status on the Filer, telnet to the filer and input the following command at the prompt.
ndmpd status

2. If the NDMP is ON, then switch the state to OFF, input the following command at the prompt.
ndmpd off

3. Try to backup again.

NDMP compatible products
http://www.ndmp.org/products/index.shtml#backup

What is "LSA" (Local System Account) ? How Powerful is this when compared to "User Account"?

2007-02-28T23:19:00.000+05:30

Why most services and application runs under the privilege of "LSA" rather then "User Account" (Such as admin account)?

Example:
Remote agent for windows server -----This service should always run under-----LSA
MS SQL$Backupexec -----This service should also run under-----LSA

Reason:
One of the fundamental rules of the NT/2000/03 security model is that any entity that accesses a domain or machine resource must authenticate itself to a security authority.
This rule applies to:
1. Users
2. Machines
3. Services.

In the case of a domain, this authority is a domain controller (DC)
In the case of a standalone machine, it's the Local Security Authority (LSA).

When a service starts up, it authenticates to a security authority, which is why you must link an account to a service.

Advantages of LSA: When you use regular user accounts to run an NT service, you must remember to change the password in the Service settings every time you change the account password. The alternative—running your service under the LSA—has the key advantage that it never requires a password change. In NT/2000/03 the LSA has no password.

You all must have noticed ,when we go to ---services applet----double click on remote agent for windows servers ---we see two accounts.

1. LSA for which we don't insert any password. we just select the radio button.
2. User account for which we specify the user and password.

LSA,Powerful?
The System account has the highest possible privileges on a local NT/2000/03 machine. On local machine it has GOD RIGHTS . However, although this account can access anything and do anything on the local machine, it has no permissions on any other machine. The System account's lack of other permissions is a logical consequence of its not having a password. On the one hand, without a password, it can't authenticate to another machine. On the other hand, not having to deal with password changes is an advantage.

2007-01-09T17:04:00.000+05:30

Sharing Windows environment with Linux using SAMBA:

Connecting LINUX box with Windows Box can be very handy while sharing documents from either side, and this can be achieved via SAMBA, there are some very good articles on the net on SAMBA, one of these articles is given below.

Learning the Samba
http://www.oreilly.de/catalog//samba/chapter/book/ch01.pdf

Today, i am going to show Mounting of Windows files on the Linux using SAMBA

1.On the Linux box, make sure under services, "SMB" is started. Go to start--Applications--system settngs---server settings--services--Check the SMB box and click start.

Usually, the script to start samba in a linux box is in one of the two following directories:

/etc/rc.d/init.d

or

/etc/init.d It might be called smb or samba.So, cd into the directory and: You start it with: ./samba start. or Just run ./samba Simply type:

]# service smb restart
]# service smb stop How to Configure Samba on RedHat Linux

2007-01-09T17:02:00.000+05:30

8. Now lets mount the “windows shared folder” (File System) called download to the mount point (download) we created on the Linux box.. Here we are using “smbfs”, that is smb file system. Windows (download) > Mounted to > Linux (mount point called download) In this example: Windows shared folder is: 10.208.117.115/download Linux Mount Point is:/mnt/download Command: # mount -t smbfs -o username=administrator,password=2fudge, debug=4 //10.208.117.115/dwonload /mnt/download/ Output: mount.smbfs started (version 3.0.10-1.4E) added interface ip=1.1.1.10 bcast=1.255.255.255 nmask=255.0.0.0connecting to 10.208.117.115 at port 445 4044:session request okserverzone is -198004044: session sedtup ok 4044: tconx ok #

For more information on “Mounting File Systems (Linux)” see this article:
http://www.itc.virginia.edu/desktop/linux/mount.html
9.From the above example its very clear that mount was successful, as there were No errors. To check the contents of the Windows shared folder “download”, navigate to /mnt/download folder and do “ls” which means listing.

# cd /mnt/download/
# cd download/# ls

10. Now you should see all the shared windows files.

Possible Error: it is mandatory and we have disabled it. 252: protocol negotiation failedSMB connection failed

Resolution: In a nutshell, the cause of the problem is the default security policy on Windows 2003 Server being set to always encrypt network connections under all circumstances. Whilst this is fine for most clients (especially Windows clients, understandably), the version of SMB that Panther uses doesn’t support encrypted connections. Apparently this support exists in Samba 3, but not on the version Hoary uses. The solution is to change the security policy to use encryption when it’s available and not otherwise. Here’s how. A. From Administrative Tools, open Domain Controller Security Settings.Go to Local Policies then Security Options. B. Scroll down to find the entry Microsoft network server: Digitally sign communications (always). Set this to Disabled. The only thing left to do is to reload the security policy, as changes don’t otherwise take effect for some time. Open up a command window and type: gpupdat /force Now, we have cross-platform data sharing using SAMBA. To know more please see our Free Learning sites

2007-01-09T17:00:00.000+05:30

Windows OS:

Before we learn or start to learn the Windows OS like XP, 2003, 2000 etc , its required to understand the basic difference between "Servers" and "Workstations".

You have to remember that, in the Linux world, there is little to no difference between a "workstation" and a "server". As a matter of fact, most Linux installation include a lot of software that make them, technically, a server. In the Windows world, there is quite a lot of difference between the Win2K "server" and "workstation" versions. With Linux, a workstation can act as a server and vice-versa. In Windows world "Workstations" means "Windows XP, ME, 98 , Windows 2k Professional", where as "Servers" means "Windows 2000" , "Windows 2003", "Windows Advanced" etc. It’s Operating System that determines whether it is a SERVER or WORKSTATION.

The only difference is the amount of software that gets installed on your machine -- For Linux, Red Hat "Server" can therefore turn your machine into a web server, an FTP server, etc. UNIX like OS : A "Unix-like" operating system is one that behaves in a manner similar to a UNIX system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. The term can include free software / open source operating systems inspired by Bell Labs' UNIX or designed to emulate its features, commercial and proprietary work-alikes, and even versions based on the licensed UNIX source code (which may be deemed so "Unix-like" that they are certified to bear the "UNIX" trademark). There is no formal standard for defining the term, and some difference of opinion is possible as to whether a certain OS is "Unix-like" or not. Unix-like systems often have Unix-like names such as AIX, IRIX, Linux, Minix, Ultrix, and XENIX. We are talking about Linux here: Having a Linux box on the VMWARE (Test Machine) can be very handy while writing on Products that deal with UNIX like OS. What is VMWARE: VMware Player lets you evaluate new or pre-release software contained in virtual machines, without any installation or configuration hassles. You can also share existing virtual machines with colleagues or friends—just use VMware Player to run any virtual machine. What is a virtual machine? A virtual machine is a computer defined in software. It's like running a PC on your PC. VMware Player runs any virtual machine created by VMware Workstation, GSX Server or ESX Server. VMware Player also supports Microsoft virtual machines and Symantec LiveState Recovery disk formats. Fore more details please see: http://www.vmware.com/ Linux on VMWARE: Having a Linux box on the VMWARE (Test Machine) can be very handy while writing on Products that deal with UNIX like OS. Setting up a Test Network with VMWARE Once the linux image is loaded on the Vmware application, one can proceed with the Steps to set the “STATIC IP” for the Linux box on test network. For complete steps with images please write to me at: mailto:ashwinpawar@rediffmail.com

2007-01-09T16:49:00.000+05:30

KM INDIA Welcomes Gary Rabideau

Gary cutting the Cake on his first visit to INDIA

KM Team ,from left: Shilpa, Ashwin, Gary, Pranab (standing behind) & Amruta.

2007-01-09T15:22:00.000+05:30

How many Protocols does NetBIOS has ?

Netbios has three protocols using 4 (2 UDP + 2 TCP) Ports:
137/udp netbios-ns NetBIOS name service 138/udp netbios-dgm NetBIOS datagram service 139/tcp netbios-ssn NetBIOS session service (Windows NT)
445/tcp netbios-ssn NetBIOS session service (New Port used by Windows 2000, Windows XP and Windows Server 2003)

137/udp netbios-ns NetBIOS name service = Allows name resolution without using a WINS server.
138/udp netbios-dgm NetBIOS datagram service = Used by applications such as the Messenger service, the Browser service, and other applications that use the mailslots interface.
139 & 445/tcp netbios-ssn NetBIOS session service = Allowing file transfers, network printing, and remote applications such as Server Manager and User Manager to function. The session service a connection-oriented, sequenced, reliable communication between two machines. The datagram service is a connectionless, unsequenced, unreliable service. netbios-ssn compares to TCP as netbios-dgm compares to UDP. NetBIOS is one of those things that exists at various layers, depending on whose book you're reading. Since NetBIOS requires some type of network and transport, it isn't a layer 3 or 4 protocol again it depends which book your are reffering.

2007-01-09T15:21:00.000+05:30

What is the Difference beteen UNIX and LINUX OS.

UNIX is a multiuser, multitasking operating system originally developed at Bell Laboratories in 1969 by Ken Thompson, Brian Kernighan and Dennis Richie. Linux was originally developed by Linus Torvalds as a small project while he was a student at the University of Helsinki in Finland. Its written from Scratch, based on the POSIX Standard (Portable Operating System Interface, the open operating interface standard accepted world-wide. It is produced by IEEE and recognized by ISO and ANSI), that defines the Way a UNIX-Like Operating System must work. All Unixes must be POSIX Compliant, no matter if it's Linux, BSD-s, HP-UX, AIX, Solaris, IRIX, etc.

UNIX is a Trademark that originally belonged to Bell Laboratories (AT&T), and has been sold to one company to another with the years (UNIX is what the owner wants it to be). Technically, Linux is not Unix but from the user's point of view, there is little difference between Linux and Unix as both systems follow roughly the same specifications.

2007-01-09T15:18:00.000+05:30

How to read Permissions of a File or Directory in Linux :

There are 3 sets of permissions for every file or directory -- owner, group, and global. For each set, there are separate read, write, and execute permissions. The owner permissions are for the owner of the file or directory.

The group permissions are for everyone in the group. The global permissions are for anyone. To see the current permissions, owner, and group for a file or directory, type the following command: ls -l This will display the contents of the directory you are in in long format.

For example the list of a file called testfile and the directory testdir would look like the following: drwxr-xr-x 2 tchin users testdir -rw-r--r-- 1 tchin users testfile The permissions are listed in the first column. The first letter is whether the item is a directory or a file. If the first letter is a d, then the item is a directory as in the first item listed above, testdir. Notice, for the file testfile, the first letter is -. The third column (tchin) tells the owner of the file/directory, and the forth column (users) is the name of the group for the file/directory. The next three letters are the permissions for the owner of the file, the next three letters apply to everyone in the group, and the last three letters are for everyone else. The read, write, and execute permissions are referred to as r,w, and x respectively.Thus, for the directory testdir above, the owner tchin has read, write, and execute permissions to the directory testdir, everyone in the group users has read and execute permissions, and everyone else has read and execute permissions. The only one who can modify or delete any file in this directory is the owner tchin.

2007-01-09T15:15:00.000+05:30

How do I determine what operating system I'm using from terminal or console ?

If you only have text on the computer or only a console to work with often you can determine what operating system you are using by using any of the below commands.

Note: On some systems the command to view what operating system and/or its version will be disabled for security reasons and not all operating systems will support all of the below commands.

1. "ver" for Dos/Windows
2. "winver" for Dos/Windows
3. "uname" for Unix/Linux Note: For all the switches always check out the help. For ex- In case of Unix/LInix type "uname --help". Additional information about the Linux version can also be found by using the below commands if the uname command is not available.

Type: cat /etc/issue Following is the example output: Red Hat Enterprise Linux AS release 3

2007-01-09T15:12:00.000+05:30

2007-01-09T15:10:00.000+05:30

How to create a "Batch File" which will delete "all the files" inside the specified folder after a Backup job. Batch file: (Can be used as post cmd)

1. Open a notepad and enter the following cmd given in step 2.

2. del C:\folder\*.* /s /q (You can specify any drive where the folder exists).

3. Save this file as a ".BAT" extension. Thats it, You can now place this file in the POST CMD section of Backup Software and delete all the files under the specified folder.

2007-01-09T15:09:00.000+05:30

How to identify version of SQL Server2k:

Execute one of the following queries against an instance of the database engine by using isql, osql, or Query Analyzer. SELECT @@VERSION Find out your version of Database Components by means of the following table. SQL Server 2000 Version and Level @@VERSION Product Level SQL Server 2000 Original Release 8.00.194 RTM: Database Components SP1 8.00.384 SP1 Database Components SP2 8.00.534 SP2 Database Components SP3, SP3a or MSDE 2000 Release A. 8.00.760 SP3 Database Components SP4 8.00.2039 SP4 Note Your product version may be different than these values if you applied a hotfix after installing the product or after installing a previous service pack. For example, @@VERSION returns a value of 8.00.818 after you apply the security fix MS03-031 to SQL Server 2000 SP3a.

2007-01-09T15:08:00.000+05:30

Tape Formats use by Backup Products:

1. Windows Backup =Microsoft Tape Format ( MTF)
2. Veritas Backup Exec = Microsoft Tape Format ( MTF)
3. EMC Legato = OpenTape Format (OTF)
4. Vertias Netbackup = Tape Archive format (TAR)

2007-01-09T15:07:00.000+05:30

Step by Step guide for Disaster Recovery of Exchange 2003:

Warning: This is a practical guide for disaster recovery for exchange and administrator(s) should perform the steps at their own consent. Author is noway responsible for sucess or failure of the restore.

1. Reinstall Windows. Reinstall the same version of Windows by running Windows Setup with the following options: -- The hardware and software configuration should match the original Exchange server, including the same components, the same version of Windows, the same service packs and hot fixes, the same drive designations, and the same server name. -- You should not join the Windows domain. Configure Windows as a standalone server in a workgroup. The server will automatically rejoin the correct domain when you restore the System State from the backup media.

2. Restore the disk drives. You should restore the system drive and any other drives containing data or applications. Select Start Restore to begin recovering the drives.

3. Recover the system state. Select the System State check box. The System State backup includes Active Directory data, Windows registry data, and other data that are not usually backed up by file and drive backups. Select Start Restore to begin recovering the System State. Restart the server. You will receive an error dialog box informing you that at least one service could not be started. The failing services are the ones that require Exchange. Windows incorrectly believes these services are configured on this server because they are listed in the System State backup. This problem will be corrected automatically when Exchange is reinstalled in disaster recovery mode.

4. Reinstall Exchange in Disaster Recovery Mode. Insert the Exchange Server 2003 CD-ROM into your CD-ROM drive. Select Run from the Windows Start menu. As the command to run, enter x:\setup\i386\setup.exe/DisasterRecovery, where x is your CD-ROM drive. Select OK to start the setup program. You must install Exchange to the same drive and directory on which it was installed on the original server. Ensure that each component that was originally installed has an action of Disaster Recovery. If all of the originally installed components are not automatically set for Disaster Recovery, you must manually select them. Running Exchange Setup in Disaster Recovery mode restores the original Exchange system configuration and services. Once you have restored the Exchange configuration, you can recover the Exchange databases.

5. Restore Online Information Store databases.

2007-01-09T15:05:00.000+05:30

What is "LSA" (Local System Account) ? How Powerful is this when compared to "User Account"?

Why most services and application runs under the privilege of "LSA" rather then "User Account" (Such as admin account)? Example: MSSQL$Applicationame ------This service always/should run under-----LSA Reason: One of the fundamental rules of the NT/2000/03 security model is that any entity that accesses a domain or machine resource must authenticate itself to a security authority. This rule applies to: 1)Users 2)Machines 3)Services. In the case of a domain, this authority is a domain controller (DC) In the case of a standalone machine, it's the Local Security Authority (LSA). When a service starts up, it authenticates to a security authority, which is why you must link an account to a service. Advantages of LSA: When you use regular user accounts to run an NT service, you must remember to change the password in the Service settings every time you change the account password. The alternative—running your service under the System account—has the key advantage that it never requires a password change. In NT/2000/03 the System account has no password. You all must have noticed ,when we go to ---services applet----double click on MSSQL$Applicationame ---we see two accounts. 1) LSA for which we don't insert any password. we just select the radio button. 2) User account for which we specify the user and password. LSA,Powerful? The Local System account (LSA) has the highest possible privileges on a local NT/2000/03 machine. However, although this account can access anything and do anything on the local machine, it has no permissions on any other machine. The System account's (LSA) lack of other permissions is a logical consequence of its not having a password. On the one hand, without a password, it can't authenticate to another machine. On the other hand, not having to deal with password changes is an advantage but at the same it can just expose the whole OS to the user.

2007-01-09T15:02:00.000+05:30

BRUSH-UP WITH SQL DATABASE and File Groups ( Very Basic) :

When a SQL database is created, two or more files are created to support that database. These files are the Primary Data File and the Transaction Log File. Primary Data Files have an extension of ".MDF" and Transaction Log Files have an extension of ".LDF". A database may also have Secondary Data Files, having an ".NDF" extension. (Note: You can actually use any extension for your files but these are recommended for consistency.)Every database must have a Primary Data File. This file contains the system tables for the database, pointers to any other files used by the database, and can also contain data. Secondary files contain any data that did not fit in the Primary. Databases do not necessarily have a secondary file, but may have one or more. The Transaction Log File contains all of the log information that may be used to recover a database. Each database has a Transaction Log File, though there may be more than one. File Group is a important segment of the SQL database and If you are wondering WHY ? Read below Imagine you have a database which is about 20 GB and its keeps growing, but there is only two tables that are getting updated frequently. Then, Instead of Backing the FULL DATABASE you can just put those tables on the file group and just backup the file group, because why should you backup the whole database when only TWO TABLE is getting updated. WHY? Save Time and Space.

Lets see how to create a File Group Creating FILE GROUP 1) Open Enterprise Manager. 2) Open your Local instance. 3) Right click on database ---Choose---create NEW. 4) Give a suitable Name---Click ok. 5) Right click on the database that you just created---Choose Properties. 6) From the Menu---Click on File Group TAB. 7) By default you will see Primary FILE GRP, Create a New FILE GRP underneath that and name it as ---SECONDARY. 8) Click on Ok....Secondary File GRP is now created. 9) Right click the database you created this time --click on ---- Data files. 10) Finally, Create a secondary file (.NDF) and give it a separate path and select SECONDARY under File Group. Now, go ahead and create tables, these tables will now be listed under secondary file group rather then Primary. That's it!

2007-01-08T18:21:00.000+05:30

ExMerge Exchange 2003:

Mailbox Merge Wizard (ExMerge) : Use the Mailbox Merge Program to extract data from mailboxes on a Microsoft Exchange Server and then merge this data into mailboxes on another Microsoft Exchange Server. The program copies data from the source server into Personal Folders (.PST files) and then merges the data, in the Personal Folders, into mailboxes on the destination server. The ability to merge data to and from an Exchange Server makes this program an invaluable tool with a variety of uses- especially during disaster recovery. The program can also replace existing data instead of merging new data if specified by the Administrator. Mailbox Merge has some limitations. Please read the tools documentation before using this program. This utility comes with the exchange CD otherwise you can also download using the link given below:

Download
http://www.microsoft.com/downloads/details.aspx?FamilyId=429163EC-DCDF-47DC-96DA-1C12D67327D5&displaylang=en

2007-01-08T18:19:00.000+05:30

What is the Linux Operating System?

Linux is an open-source operating system published under the GNU Public License. Open source means that anyone is free to use and modify any of the actual source code. Companies and individuals can change the way the operating system works to suit their own personal or business needs. Linux was originally developed by Linus Torvalds while he was a student at the University of Helsinki in Finland. Torvalds, originally working with Minx, (a small UNIX system) decided to create an operating system which would exceed Minx standards. His development began in 1991 when he released version 0.02. Since then Linux has undergone drastic changes. There are now many different distributions of Linux (sometimes referred to as flavors) which all use the same Kernel. This Kernel is still being developed by Tornados and a group of programmers and releases are more and more frequent. The current Kernel version is 2.6 as of the writing of this document.The Linux operating system is touted for its speed, minimal hardware requirements, security and remote administration. Linux is a fully featured operating system which doesn't have to cost a dime. You download many different distributions directly from the Internet and the support community is huge. Because of Lenox's speed and stability it has become the operating system of choice for most types of servers and permeates the entire web market. In addition there is a plethora of software available free of charge for Linux.If graphics is your thing and the whole text based mode scares you a little then you should check out the X Window system. There are a few different interfaces available to choose from the two main ones being NOME and KED. Both of these have tons of features and are always being updated.On a side note, you may see the Linux around the web he's an overweight penguin who sits contentedly on whatever area he happens to be perched on. His name, for the record, is Tux. Tux was chosen by Tornados to represent the Linux operating system years ago and he seems to have done a good job of catching on.

For basic linux Commands please refer to the link given on the Right hand side.

General IT stuff....

How to edit configuration files using "wrfile" command in NetApp DataONTAP.

I have bought 160GB USB Drive, but why I only get a disk size of 149 GB, where is the remaining 11 GB gone ?

Virtual Floppy in a Virtual World:

What is ports ? Ports are ports whether it is windows or Unix.

Test disaster recovery (MBR curruption) of Redhat AS 4 on vmware workstation 5:

Free VMware Workstation without the need to create your own virtual machine:

What is virtualization ? By, Vmware.

Basic's of storage networks (An insight into - How we got to, where we are today..')

SAN explained in most simplest way.......

All SAN aspirants, a peek inside the server room, check this out.

Welcome to the world of virtualization: vmware

What is GRUB, it is the first thing you see When you boot Solaris, Redhat or other UNIX-like distro..

Linux is a "KERNEL" not an Operating System :

Love Linux not necessarily marry : -Ashwin

Installing Samba on Solaris:

What is Telnet and SSH?

Difference between BLOCK and FILE level Data : -Ashwin

Affordable Windows iSCSI storage area network : Backup Exec backs up data to ISCSI drive.

Interview questions for tech companies : Crack it.

NDMP ended the monopoly of the Backup software Vendors and File Server vendors :

FIler Definition: -Ashwin

Backup and Restore : By Dilip Naik

VMware Infrastructure 3 Demo: Magical Suite for IT People / Department.

Linux Filesystem Hierarchy - Part One , From Binarysignal

Linux Filesystem Hierarchy - Part Two, From Binarysignal

BAD PASSWORD: it is based on dictionary word | Linux password issues | -Ashwin

Penguin Gallery : Funny, Cute and artistic penguins...

Penguin the Linux Mascot : Story goes like this..

SAMBA Permission Vs Linux Permission: Who takes precedence

New Samba 4.0 targets Active Directory

Learning Tutorials: Linux | UNIX | Networking

IBM ENTRY SAN: DS3000 Series, is a S.A.F.E.R option

What is Samba? -Ashwin

How 2 Setup Linux (network, smb, apache)

15 years Linux: past and future (video)

Sun Fire x4500 demonstration:

Hardware-related questions about Complete PC Restore :

Practical approach to ISCSI: - My personal views & understanding. - Ashwin

I-SCSI network , really cool concept. It has scalability and capability.-Ashwin

what the hell is i-SCSI ? -Ashwin

Wondering how the Internet really works? Learn TCP/IP in most enjoyable way.

OSI Model Training Tutorial (1 of 3) : Networking for beginners.

Network Attached Storage: NAS Device from VANTEC.

eCDN (enterprise content delivery network)

Overview of Enterprise Storage : For all the storage techies.

Storage Networking Training Video: SAN

Learning Linux : Class room update.

Cool Computer Program: Engineers you will love it.

Networking and Storage - How much you know ?

Don't *switch* to Linux, *migrate* there :

How realistic is it for the average Windows user to install and use a Linux-based OS ?

Desktop environments for Linux:

The power of competition: - Ashwin

Symantec Backup Exec™ System Recovery :(formerly Symantec LiveState™ Recovery)

See the SAN Storage Setup Guide by HP: Build your company's first SAN

Recommended PORT consideration for Firewall/TCP Filtered environment:

Storage Jobs - Storage Area Network or SAN jobs :

The Difference Between FTP and HTTP :

How to clear the Browsing HISTORY and the FORMS such as search queries and your search pattern.

BRUSH-UP WITH SQL DATABASE : Very Basic

Error: SMB signing is mandatory and we have disabled

Knowledge Management:

Career in SAN Technical Support:

Introduction to storage systems:

What is ISCSI and How iSCSI Works:

Introduction: Storage Area Networks (SAN) :

SAMBA for NEWBIES...

what is Proprietary Operating System:

Data ONTAP by Network Appliance :

GuardianOS from Snap Appliance :

Microsoft Windows Storage Server 2003 :

iptables firewall

Can Backup Exec for Windows Servers encrypt data on media?

How to enable ARCHIVELOG mode in Oracle 10g (10.1)..

Recommended PORT consideration for Firewall/TCP Filtered environment:

Funny Video, i bet u go mad: NTU Student survey - Funny comments

Network Data Management Protocol (NDMP/10000)...

RPM Overview ............

What is "NAMED PIPES" in Unix\LINUX..

Don't switch to Linux, migrate there :