Tuesday, February 5, 2013

The Hitchhikers Guide To ESXTOP Counters

For all the other performance people out there that spends time using esxtop to do deep analysis of ESX performance, there is a great document that you really should know about.  It is called vSphere Monitoring and Performance for vSphere 5.1 / vCenter 5.1 / ESX 5.1.

My favorite section is a detailed list of all the esxtop counters and exactly what they mean and how they inter-relate.

For example, I had a question about what is the difference between the %USED and %RUN for a VM.  On page 155 and 156 of this great document it gives you the specific formula for %USED, which is:


It also explains in the %RUN definition that on systems with hyperthreading enabled, the %RUN value does not account for hyperthreading.  This can cause %RUN to be twice as large as %USED.  But wait this can't be possible based on the formula - except in this case it is because %USED accounts for hyperthreading.

Another mystery of the universe is solved with the help of the vSphere Monitoring and Performance guide.

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