Finding out host memory usage by VirtuCache

This is an advanced debug use case. It is usually of no concern to VirtuCache, Storage and VMware Administrators. But if you would like to find out the memory usage by VirtuCache, search vmkernel logs for

“vnx2: cache-index: mem-usage:”

This log line is emitted very once every 5-10 minutes.

The below log lines (in vmkernel logs)  indicate that the memory limit for VirtuCache is reached, in which case VirtuCache will turn off, reconfigure memory allocated to it and automatically restart. However both the below conditions should rarely happen, but even if they do happen then VirtuCache will restart gracefully with new memory allocation settings. The two cases where we have experienced VirtuCache reaching the memory limit condition is when you have large amounts of write IO, typically backup IO, exceeding 100MBps or so per host across many VMs, or IO is happening from many VMs (>100) AND many Datastores (>50) on each host (say if only a few VMs are on each Datastore and there are many Datastores).

“Memory limit for cache index reached”

“Disabling caching, Reconfigure memory sizing”