What's an acceptable sampling rate with Perfmon? Obviously, the more often we sample, the more our performance sampling has an effect on the performance on the machine. I'm hoping someone out there has a good rule of thumb for such a thing.
Evidence and statistics would be even better, but I'd be happy with generally accepted best practices.
The sample rate depends of course on the time you sample and the time you want to save the data and work with it later on.
Brent Ozar who has a pretty nice video about configuring PerfMon best practices using it to monitor sql and hardware performance. He recommends 15 seconds sample rate. For long time statistics. If you use Perfmon on a daily basis running for 6 hours it will generate nearly 1,5k of samples which is fine for me.
Brent Ozar Perfmon
If you are chasing a critical issue which is happening right now, you will lower the rate of course. But for overall collection of data a rate of 15 seconds which means 4 per minute is working well.
It always depends on what you monitor. Vmware's Suggestions to monitor virtualisation
are the following :