Basic Overview and use of NMON on CentOS 5

nmon for Linux – Nigel’s performance Monitor for Linux is a wonderful Swiss Army Knife for Performance Information.You can display multiple screen on the same windows and get information on CPU, Memory, NFS, Network, Disks, Resource, kernel etc

nmon has single binaries for each operating system including Red Hat, SUSE, Ubuntu, OpenSUSE, Fedora etc. Using the binary is as simple as starting the executable like

$ ./nmon_x86_64_rhel54

Using nmon in basic mode. For more information, do read the nmon for Linux Getting Started for more details

  1. To quit, just hit “q”
  2. Most of the rest are toggled commands i.e. hit c to see the CPU stats and hit c again to remove CPU stats.
  3. For disk graphs hit d and you will see a 50 column graph of the read and write busy percentages
  4. For disk numbers hit D and if you hit D again you see different information eventually hitting D will close this section

Using nmon for Linux in data capture mode

  1. Capturing a small sample file: nmon -f -s 2 -c 30
  2. -f means the data will be saved and not displayed on the screen
  3. -s 2 means data capture every 2 seconds
  4. -c 30 means 30 data points or snap shots
  5. Do note that the nmon runs like a daemon process in the background. nmon will continue to run till completion whether you connect or log-off.
  6. You can check whether the nmon is running by “ps -ef | grep nmon”
  7. Resulting file is xxx.nmon

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