Shell Script: Create Linux Bootable USB Sticks

Posted on in Categories Howto, Linux, Linux desktop, Linux distribution, Perl last updated February 27, 2008

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?

Posted on in Categories High performance computing, Howto, Linux, Linux Scalability, Storage last updated November 12, 2007

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

Posted on in Categories CentOS, High performance computing, Howto, Linux, Linux Virtualization, RedHat/Fedora Linux, xen last updated October 18, 2007

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

Posted on in Categories Backup, Linux, Shell scripting, Tips last updated August 22, 2006

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

Posted on in Categories Howto, Linux, Monitoring, OpenBSD, UNIX last updated June 15, 2006

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

Monitoring hard disk health with smartd under Linux or UNIX operating systems

Posted on in Categories Howto, Linux, Monitoring, RedHat/Fedora Linux, Suse Linux, Sys admin, Tips, Ubuntu Linux last updated May 3, 2006

smartd is SMART Disk Monitoring Daemon for Linux. SMART is acronym for Self-Monitoring, Analysis and Reporting Technology (SMART) system built into many ATA-3 and later ATA, IDE and SCSI-3 hard drives. The purpose of SMART is to monitor the reliability of the hard drive and predict drive failures, and to carry out different types of drive self-tests.

smartd works with following operating systems:

  1. Linux
  2. *BSD
  3. Windows
  4. Solaris etc

How do I Install smartd?

However, smartd is not installed by default. Following are distribution specific steps to install smartd:

Debian Linux:
# apt-get install smartmontools
Red hat/Fedora Linux:
# rpm –ivh kernel-utils
OR
# up2date kernel-utils
OR if you are using Fedora Linux
# yum kernel-utils
FreeBSD:
# pkg_add -r -v smartmontools

Before configuring hard disk for SMART monitoring make sure your hard disk is SMART capable:
# smartctl -i /dev/hda
Output:

smartctl version 5.34 [i686-pc-linux-gnu] Copyright (C) 2002-5 Bruce Allen
Home page is http://smartmontools.sourceforge.net/

=== START OF INFORMATION SECTION ===
Device Model:     SAMSUNG SV2002H
Serial Number:    0395J1FR904324
Firmware Version: RA100-04
User Capacity:    20,060,651,520 bytes
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   6
ATA Standard is:  ATA/ATAPI-6 T13 1410D revision 1
Local Time is:    Tue May  2 15:44:09 2006 IST

SMART support is: Available - device has SMART capability.
SMART support is: Enabled

You can configure the smartd daemon by editing the file /etc/smartd.conf. 

In above output the lines:
SMART support is: Available – device has SMART capability.
SMART support is: Enabled

Indicates that it is SMART capable and it is enabled.

Configure SMARTD

Debian Linux

  • Enable smart by editing /etc/default/smartmontools file.
  • Smart Configuration file: /etc/smartd.conf
  • Start/Stop smart: /etc/init.d/smartmontools start | stop

Red Hat Linux

  • Enable smart by editing /etc/smartd.conf file.
  • Smart Configuration file: /etc/smartd.conf
  • Start/Stop smart: /etc/init.d/smartd start | stop

FreeBSD

  • Enable smart by editing /etc/rc.conf file (add line smartd_enable=”YES”).
  • Smart Configuration file: /etc/smartd.conf
  • Start/Stop smart: /usr/local/etc/rc.d/smartd.sh start | stop

Example

You can put following directives in Smart Configuration file:
(a) Send an email to [email protected] for /dev/sdb:
/dev/sdb -m [email protected]
(b) Read error log:
# smartctl -l error /dev/hdb
(c) Testing hard disk (short or long test):
# smartctl -t short /dev/hdb
# smartctl -t long /dev/hdb

Caution smartd is a monitoring tool not a backup solution. Always perform data backup.

See also:

  • More information on the smarttool see official home page.
  • Read man page of smartd and smartd.conf for configuration help.