NMON is short for Nigel’s Performance Monitor, it is available on AIX Systems, Solaris (with Sarmon), and Linux Systems.

  • nmon for Linux is open source under GPL:

  • nmon for AIX is not open source but is integrated into topas command from:

    • AIX 5.3 TL09
    • AIX 6.1 TL02


This is a great “all in one” Performance Monitor tool that provides a very large amount of system performance information, and it can be used in different scenarios.

The first way to use NMON is running the “nmon” command in terminal, which opens a Real time monitoring terminal interface, giving you access to many system metrics within a single screen:


nmon is also very often used as a Capacity Planning and Performance tool by running the nmon process in a csv generating mode all along it’s run time, for later cold Analyse.

Here are some useful links about NMON:

Analysing NMON csv data is not easy because it has a very specific format Splunk cannot directly manage. (one big problem stands in the event time stamp identification which is very uncommon and defined by a non time stamp pattern)

This is why I decided to develop this App, based on my own professional experience in Unix systems Capacity Planning, to provide to anyone interested a powerful too to Analyse NMON data with an Enterprise Class Application.

How it works

In a few words, here is how the App works:

  • The Nmon core application contains all the views, data models, configurations and related objects
  • The TA-nmon which is the technical addon for the Nmon Performance application contains binaries and scripts to manage the nmon data
  • The TA-nmon once installed starts immediately to collect and transforms nmon performance and configuration data
  • The default configuration indexes data into the “nmon” index (by default)

Splunk Data structure


Performance metrics data ordered by the key “type” which corresponds to the nmon section metric item (CPU_ALL, LPAR…):

index=nmon sourcetype=nmon_data




Configuration data extracted by nmon2csv converters, corresponds to AAA and BBB* sections of nmon raw data:

index=nmon sourcetype=nmon_config




Output of the script which is responsible for nmon instances launches:

index=nmon sourcetype=nmon_collect




Output of nmon2csv Python and Perl converters (conversion of nmon raw data into csv data):

index=nmon sourcetype=nmon_processing




Output of the script (interface to | which is responsible for nmon raw data file cleaning:

index=nmon sourcetype=nmon_clean



Available packages

There are different packages: