nmon Performance Monitoring Tool

Audience: Systems Administrator

Date: May 20, 2002

The nmon and nmon_analyzer are free tools from IBM that are useful for displaying and analyzing AIX performance.

The nmon tool is similar to "topas", which displays real-time AIX performance statistics. But unlike "topas", nmon presents more information and can capture data for analysis and presentation.

The nmon_analyzer tool analyzes the captured performance data. It can create a spreadsheet showing graphs of performance trends. Some of the nmon_analyzer metrics include:

• Calculation of weighted averages for hot-spot analysis
• CPU utilization by processor - useful in identifying single-threaded processes
• ESS vpaths showing device busy, read transfer size, and write transfer size by time of day
• Total system data rate by time of day - useful in identifying I/O subsystem and SAN bottlenecks
• EMC hdiskpower devices
• Data rates by network adapter

You can download both tools from:

Old: http://www-1.ibm.com/servers/esdd/articles/analyze_aix /
nmon (2/26/04): http://www-106.ibm.com/developerworks/eserver/articles/analyze_aix/
nmon analyzer (2/26/04): http://www-106.ibm.com/developerworks/eserver/articles/nmon_analyser/