Happy Birthday Debian Linux

last updated in Categories Debian Linux, GNU/Open source

Debian is known for strict adherence to the Unix and free software philosophies. Debian is also known for an abundance of options — the current release includes over twenty-six thousand software packages. Today, Debian turns 15 – HAPPY BIRTHDAY!!!

Shell Script: Create Linux Bootable USB Sticks

last updated in Categories Howto, Linux, Linux desktop, Linux distribution, Perl

This may come handy, from the project page:

Mk-boot-usb is a perl script to create multiple-bootable usb sticks (usb keys / usb flash drives). It wipes out an entire usb stick, partitions it, creates file systems on it, installs grub, and installs a minimal linux on it. Mk-boot-usb is meant to speed up and lower the barrier of entry for creating bootable usb sticks. The usb stick will immediately become bootable (using the minimal linux), and more useful distributions can then be installed into other partitions manually simply by (1) copying any Live CD into each partition (2) modifying grub’s configuration file.

=> Mk-boot-usb: a Script to Create Multiple-Bootable USB Sticks

Related: How to Create Bootable Linux CD

Can I boot My Linux Server from iSCSI or SAN or NAS network attached storage?

last updated in Categories High performance computing, Howto, Linux, Linux Scalability, Storage

My previous article related to iSCSI storage and NAS storage brought a couple of questions. An interesting question from my mail bag:

I’ve 5 Debian Linux servers with HP SAN box. Should I boot from SAN?

No, use centralized network storage for shared data or high availability configuration only. Technically you can boot and configure system. However I don’t recommend booting from SAN or any other central server until and unless you need diskless nodes:

[a] Use local storage – Always use local storage for /boot and / (root) filesystem

[b] Keep it simply – Booting from SAN volumes is complicated procedure. Most operating systems are not designed for this kind of configuration. You need to modify scripts and booting procedure.

[c] SAN booting support – Your SAN vendor must support platform booting a Linux server. You need to configure HBA and SAN according to vendor specification. You must totally depend upon SAN vendor for drivers and firmware (HBA Bios) to get thing work properly. General principle – don’t put all your eggs in one basket err one vendor 😉

[d] Other factors – Proper fiber channel topology must be used. Make sure Multipathing and redundant SAN links are used. The boot disk LUN is dedicated to a single host. etc

As you can see, complications started to increases, hence I don’t recommend booting from SAN.

How to: Install and Setup XEN Virtualization Software on CentOS Linux 5

last updated in Categories CentOS, High performance computing, Howto, Linux, Linux Virtualization, RedHat/Fedora Linux, xen

Xen is a free open source software virtual machine monitor for Intel / PowerPC architectures. It is software that runs on a host operating system and allows several guest operating systems to be run on top of the host on the same computer hardware at the same time (just like VMWare software). Luckily Installing and managing XEN is quite easy under CentOS 5 Linux.

Linux Get List of Installed Software for Reinstallation / Restore All the Software Programs

last updated in Categories Backup, Linux, Shell scripting, Tips

Hardware and software failures are part of life. And that is why you need to have a backup plan. I have already written about backing up files and MySQL databases. There is no need to backup all installed binaries and software programs. The following tip will not just save your time, but both Debian and RHEL based distro can be updated instantly.

Linux and UNIX interactive, process and users monitoring tool

last updated in Categories Howto, Linux, Monitoring, OpenBSD, UNIX

whowatch is a interactive, ncurses-based, process and users monitoring tool, which updates information in real time. This is a perfect tool for local and remote servers. With this tool you can easily answer following question:
How do I know who are logged on in using telnet , ssh, ftp etc and what resources are they are using?

Output of whowatch command

It displays information about the users currently logged on to the machine, in real-time. Besides standard information (login name, tty, host, user’s process), the type of the connection (ie. telnet or ssh) is shown. Display of users command line can be switch
to tty idle time. Certain user can be selected and his processes tree may be viewed as well as tree of all system processes. Tree may be displayed with additional column that shows owner of each process. In the process tree mode SIGINT and SIGKILL signals can be sent to the selected process. Killing processes is just as simple and fun as deleting lines on the screen.

How do I install whowatch tool?

If you are using Debian Linux, type the following command:
# apt-get install whowatch

If you are using FreeBSD, type the any one of the following command:
# pkg_add -r -v whowatch

You can also use ports collection under FreeBSD:
# cd /ports/sysutils/whowatch
# make; make install; make clean

ALTERNATIVELY, download from official website.

How do I use whowatch?

Simply type whowatch at command prompt:
$ whowatch

Default output:
Who watch output

Detailed information about process / user

who-watch-output-3.png

Menu (press F9 key to activate menu option)

who-watch-output-4.png

Linux creating CD-ROM ISO images from a CD, DVD, Blu-ray

last updated in Categories FreeBSD, Howto, Linux, Solaris, UNIX

dd is a perfect tool for copy a file, converting and formatting according to the operands. dd command works on Linux and a Unix-like system whose primary job is to convert and copy files. It can create exact CD-ROM ISO image or create a new CD/DVD iso image. This is useful for making a backup, as well as for hard drive installations, require a working the use of ISO images.