How do I monitor system performance using nmon?

nmon is a free console-based performance monitoring tool from IBM. It works on both AIX and RHEL.

If nmon is not already installed, you must first install it:

• How do I install nmon on Linux?
• How do I install nmon on AIX?

To use nmon:

View a step-by-step screencast of this process:

• Log into your server as root using a terminal emulator such as PuTTy (see also: How do I use PuTTy with my Eclipse server?)
• (AIX only) Set the terminal emulation type to match the PuTTy console:

  export TERM=xterm

• Run:

  nmon

• Press the appropriate keys to launch or close various monitoring windows. Type “h” for help. Here are some common views:
  • “t”: display top processes
  • “t” then”u”: display top processes by CPU utilization and show command line arguments
  • “c”: display CPU utilization
  • “l”: display longer-term CPU utilization averages
  • “d”: display disk I/O graphs
  • “h”: display help

Resources:

• IBM DeveloperWorks Wiki: nmon for AIX Performance Monitoring
• IBM DeveloperWorks: nmon performance: A free tool to analyze AIX and Linux performance
• nmon