check_sys is a multiple purpose plugin that performs the following checks:

  • disk space
  • process list
  • swap utilization
  • load (run queue)
  • syslog
  • errpt (AIX)

The results are combined into a single line message. The most critical error code is chosen as the final plugin error code result. The plugin also checks new entries which have been added to the system log since the last execution of the plugin.


  • Written in C (for speed and portability)
  • Configuration can be completely delegated to the server's administrators (which do not need to have access to the Nagios server)
  • Fewer service checks and significantly less configuration overhead
  • Support for failover cluster services
  • Currently runs under Linux, Solaris, Tru64, AIX and *BSD


  • Changes since version 1.6:

    • Added '-s' switch (support for failover cluster services)
  • Changes since version 1.5:

    • df command may output multiple lines per mountpoint under Linux. This is now supported