#StackBounty: #aix #cpu-usage #sar Making sense of the output sar on AIX

Bounty: 100

I’m trying to understand some data that has been pulled from SAR. I have three main questions about this. Ultimately, I’d like to determine how many CPUs were idle at each sampling interval across a cluster of servers.

  1. Many of the CPUs are not showing up in every entry. Is this expected and What exactly does that mean? Is it related to #2?
  2. There are unused lines (CPU = U). The documentation says “U indicates the system-wide Unused capacity”. I can’t find a precise definition of “system-wide Unused capacity” or any definition at all, really. I’m not sure how to interpret a line that tells something like “the unused capacity was 70% idle.”
  3. Lastly, I’m unsure of how the ‘-‘ or ‘all’ line is calculated. I would think it’s the average of all the CPUs but when I do the math across all CPUs, I get a vastly different answer than what is on that line. Can anyone tell me exactly what goes into that calculation?

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