High latency because insufficient RAM or SSD capacity assigned to VirtuCache

If you have small amounts of RAM or SSD (less than 256GB) assigned to VirtuCache, and you have VMs/Hosts that do large amounts of storage IO (greater than 20 MBps per VM or 100MBps per host), then this situation might result in VirtuCache cache media running full at all times and a low host level cache hit ratio (In VirtuCache GUI > click on Hosts tab > you will see Host level Cache Hit % and Cache Media usage on this screen), and this in return could result in high read / write latency at the VM level since VirtuCache is swapping old data in cache with new at a fast clip. The solution for this is to increase cache capacity or reduce the number of VMs under caching policy.
You will not encounter this problem with VirtuCache cache media size greater than 960GB.