Verify PVS vDisk System Cache When Using CIFS
How to verify your Citrix PVS Servers are correctly caching the vDisks and reading from system cache and not from back end storage.
- Download Microsoft Sysinternal RAMMap.
- Use PerfMon.
A important performance counter that can be used to verify if PVS servers are optimally streaming to target devices is ‘Copy Read Hits %’ for the object Cache.
This value reports the percentage of read requests that are successful by reading from the PVS system cache. If a request is missed, that data will have to be retrieved from storage. With PVS, this means the reads will come from the storage where the vDisks reside, increasing the impact on the back end storage and ultimately increasing the time to stream to target devices.
Perfmon reports can be set up to gather data for each of your PVS servers that are streaming to target devices. Start you data collector during production and leave it run for at least an hour to gather good reporting data.
Citrix recommends that Copy Read Hits % should average should be above 95%. To gain additional insight into which files are being cached into RAM you can use SysInternal RAMMap.
