To troubleshoot memory performance in a VMware vSphere environment, you should monitor the memory performance very carefully. In this aspect, you should monitor the following counters:
- Average memory active: The memory estimated to be used, based on recently touched memory pages.
- Average memory swapped in or out: Virtual memory swapped to or from disk.
- Average memory swapped: Total amount of memory swapped out. This indicates a possibility (with an unknown likelihood) of poor performance in future.
To step through this recipe, you will need a running ESXi Server, a couple of running VMs with VMware Tools installed, and vSphere Web Client. No other prerequisites are required.