Fedora – Ramdisk creation

In Fedora, ramdisks are not created by default as is the case with RHEL. So, if you need to get Ramdisks on Fedora, then you can do this:

sudo yum install MAKEDEV

This will create some default Ramdisk’s in the “/dev” directory. Now, if you need to change anything then feel free to go to “/etc/makedev.d” and feel free to change these files.

The Fedora Project logo
The Fedora Project logo (Photo credit: Wikipedia)

 

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10 Useful Sar (Sysstat) Examples for UNIX / Linux Performance Monitoring

10 Useful Sar (Sysstat) Examples for UNIX / Linux Performance Monitoring

by Ramesh Natarajan on March 29, 2011

Using sar you can monitor performance of various Linux subsystems (CPU, Memory, I/O..) in real time.

Using sar, you can also collect all performance data on an on-going basis, store them, and do historical analysis to identify bottlenecks.

Sar is part of the sysstat package.

This article explains how to install and configure sysstat package (which contains sar utility) and explains how to monitor the following Linux performance statistics using sar.

  1. Collective CPU usage
  2. Individual CPU statistics
  3. Memory used and available
  4. Swap space used and available
  5. Overall I/O activities of the system
  6. Individual device I/O activities
  7. Context switch statistics
  8. Run queue and load average data
  9. Network statistics
  10. Report sar data from a specific time

This is the only guide you’ll need for sar utility. So, bookmark this for your future reference.

I. Install and Configure Sysstat

Install Sysstat Package

First, make sure the latest version of sar is available on your system. Install it using any one of the following methods depending on your distribution.

 sudo apt-get install sysstat (or) yum install sysstat (or) rpm -ivh sysstat-10.0.0-1.i586.rpm

Install Sysstat from Source

Download the latest version from sysstat download page.

You can also use wget to download the

 wget http://pagesperso-orange.fr/sebastien.godard/sysstat-10.0.0.tar.bz2

tar xvfj sysstat-10.0.0.tar.bz2

cd sysstat-10.0.0

./configure --enable-install-cron

Note: Make sure to pass the option –enable-install-cron. This does the following automatically for you. If you don’t configure sysstat with this option, you have to do this ugly job yourself manually.

  • Creates /etc/rc.d/init.d/sysstat
  • Creates appropriate links from /etc/rc.d/rc*.d/ directories to /etc/rc.d/init.d/sysstat to start the sysstat automatically during Linux boot process.
  • For example, /etc/rc.d/rc3.d/S01sysstat is linked automatically to /etc/rc.d/init.d/sysstat

After the ./configure, install it as shown below.

 make

make install

Note: This will install sar and other systat utilities under /usr/local/bin

Once installed, verify the sar version using “sar -V”. Version 10 is the current stable version of sysstat.

 $ sar -V sysstat version 10.0.0 (C) Sebastien Godard (sysstat  orange.fr)

Finally, make sure sar works. For example, the following gives the system CPU statistics 3 times (with 1 second interval).

 $ sar 1 3 Linux 2.6.18-194.el5PAE (dev-db)        03/26/2011      _i686_  (8 CPU)

01:27:32 PM       CPU     %user     %nice   %system   %iowait    %steal     %idle 01:27:33 PM       all      0.00      0.00      0.00      0.00      0.00    100.00 01:27:34 PM       all      0.25      0.00      0.25      0.00      0.00     99.50 01:27:35 PM       all      0.75      0.00      0.25      0.00      0.00     99.00 Average:          all      0.33      0.00      0.17      0.00      0.00     99.50

Utilities part of Sysstat

Following are the other sysstat utilities.

  • sar collects and displays ALL system activities statistics.
  • sadc stands for “system activity data collector”. This is the sar backend tool that does the data collection.
  • sa1 stores system activities in binary data file. sa1 depends on sadc for this purpose. sa1 runs from cron.
  • sa2 creates daily summary of the collected statistics. sa2 runs from cron.
  • sadf can generate sar report in CSV, XML, and various other formats. Use this to integrate sar data with other tools.
  • iostat generates CPU, I/O statistics
  • mpstat displays CPU statistics.
  • pidstat reports statistics based on the process id (PID)
  • nfsiostat displays NFS I/O statistics.
  • cifsiostat generates CIFS statistics.

This article focuses on sysstat fundamentals and sar utility.

Rest here: http://www.thegeekstuff.com/2011/03/sar-examples/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+TheGeekStuff+%28The+Geek+Stuff%29&utm_content=Google+Reader
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Fedora Linux – Display information about users currently logged on – whowatch

Here is description of program/utility to display the currently logged in user in a Linux box (tried on Fedora 13 Goddard):

Whowatch is an interactive console utility that displays informations about the users currently logged on to the machine, in real time. Besides standard information (login, tty, host, user\’s process) you can see type of login (ie. ssh, telnet). You can also see selected user\’s processes tree or all system processes tree.  In the process tree mode there is ability to send INT or KILL signal to selected process.

First the installation:

1
<a class="\&quot;zem_slink\&quot;" title="\&quot;Sudo\&quot;" rel="\&quot;homepage\&quot;" href="\">sudo</a> yum install whowatch

Here are the screenshot\’s if you are interested:

\"Screenshot-whowatch\"

Press enter to see the process\’s running for that user:

\"Screenshot-whowatch

Press \”t\” to view the init tree and try other commands listed in the menu below 🙂

\"Screenshot-whowatch

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