nmon analyser -- A free tool to produce AIX performance reports

Produce a wealth of report-ready graphs from NMON output

Searching for an easy way to create high-quality graphs that you can print, publish to the Web, or cut and paste into performance reports? Look no further. The nmon_analyser tool takes files produced by the NMON performance tool, turns them into Microsoft Excel spreadsheets, and automatically produces these graphs.


Stephen Atkins (steve_atkins@uk.ibm.com), IBM pSeries Technical Support, IBM

Stephen Atkins works in the IBM eServer pSeries Technical Support Advanced Technology Group. He is a specialist in pSeries hardware, systems design, and sizing. The nmon_analyser tool was developed to assist performance specialists interpret nmon output and is used extensively inside IBM. You can contact him at steve_atkins@uk.ibm.com.

19 April 2006 (First published 15 November 2003)

Also available in Chinese Russian

Usage notes: The nmon_analyser tool is NOT OFFICIALLY SUPPORTED. No warrantee is given or implied, and you cannot obtain help with it from IBM.

The tool currently comes in the form of a spreadsheet for use with Microsoft® Excel™ 2000 or later.

The nmon_analyser tool is designed to work with the latest version of nmon, but it is also tested with older versions for backwards compatibility. The tool is updated whenever nmon is updated, and at irregular intervals for new function. To place your name on the e-mail list for updates, contact Stephen Atkins.

Benefits of the tool

The nmon_analyser tool is helpful in analyzing performance data captured using the nmon performance tool. It allows a performance specialist to:

  • View the data in spreadsheet form
  • Eliminate "bad" data
  • Produce graphs for presentation to clients

The tool also automatically produces graphs for each major section of output.

In addition, the tool performs analyses of the nmon data to produce:

  • Calculation of weighted averages for hot-spot analysis
  • Distribution of CPU utilization by processor over the collection interval -- useful in identifying single-threaded processes
  • Additional sections for IBM TotalStorage® Enterprise Storage Server (ESS) vpaths showing device busy, read transfer size, and write transfer size by time of day
  • Total system data rate by time of day, adjusted to exclude double-counting of EMC hdiskpower devices -- useful in identifying I/O subsystem and SAN (Storage Area Network) bottlenecks
  • Separate sheets for EMC Corporation (EMC) hdiskpower and ESS DS8000 (formerly FAStT) dac devices
  • Analysis of memory utilization to show the split between computational and non-computational pages
  • Total data rates for each network adapter by time of day
  • Summary data for the TOP section showing average CPU and memory utilization for each command

New features

The new features for the nmon_analyser tool now include:

  • Support for AIX® 5.3 and micro-partitions (NMON10)
  • Support for input files with greater than 65K lines
  • Improved graph sizing and positioning
  • Option to specify which sheets are analysed
  • Support for printing -- with automated pagination
  • Automated Web publishing -- in PNG or GIF formats

Installing the tool

  • The tool is distributed as a .zip file and contains .xls files, comprehensive user documentation, a sample input file, a shell script for aiding National Language conversions, and a Perl program for splitting large input files. Installation simply requires unzipping the package to an appropriate directory.

Obtaining the tool

The following download option is available:

Sample output

Main chart showing CPU and I/O utilization during the collection interval:
Main chart showing CPU and I/O utilization during the collection interval:
Optional chart showing vpath service times:
Optional chart showing vpath service times:


Comprehensive documentation is included in the distribution. Available in Microsoft Word, the documentation includes details of how to collect data from nmon, how to use the analyzer, national language issues, guidance on interpreting the data, and detailed explanations for all fields generated by nmon.



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