Currently reading around the subject on collecting and analysing performance stats in a VMware environment…..
A useful article I stumbled across:
http://searchvmware.techtarget.com/tip/VMware-vSpheres-built-in-performance-monitoring-tools
Whilst it doesn’t tell you how to use the tools, it gives a good summary of what the tools are….
In addition to VMware’s own perf mon doc: http://pubs.vmware.com/vsphere-51/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-51-monitoring-performance-guide.pdf
I also found a whitepaper by the same author but for Solarwinds: http://solarwinds-marketing.s3.amazonaws.com/solarwinds/whitepapers/VM_whitepaper_Perform_Management.pdf
Obviously most people use esxtop…. so info about this tool can be found here: http://communities.vmware.com/docs/DOC-9279
As always, there’s a good article on Yellow Bricks about esxtop: http://www.yellow-bricks.com/esxtop/
The Virtual Unknown 