1 Reply Latest reply: Nov 5, 2009 2:14 PM by user4994457 RSS

    Solaris 10: Load Average versus Idle Percentage

    807567
      I have a Netra 240 running Solaris 10.

      When I look at the Load Average statistics mapped over an extended period, I see that the averages are consistently greater than 2. According to "Solaris Performance and Tools", this might be cause for concern because it could mean that the CPUs are getting saturated.

      Over the same period of time, I see that idle time is in the mid-70% range.

      It almost seems like this shouldn't be happening.

      Does anyone have a rational explanation for why the Load Average would be so high for a relatively idle server?

      Help is appreciated.

      George
        • 1. Re: Solaris 10: Load Average versus Idle Percentage
          user4994457
          Load average represents a damped "average" of how many jobs are running or trying to run.

          If your machine has 1 cpu or 24 cpus, and you have two cpu-bound jobs running, your load average should be close to 2.

          On a 1 CPU machine, your CPU will tend to be 0% idle, and each job will be running about half the time.
          On a 2 CPU machine, your CPU will tend to be 0% idle, and each job will be running all the time.

          With more than 2 CPUs, your idle% will increase, but your load average will still be 2.

          --
          Darren