Why are Write Latencies High Even When the EMC Unity Appliance has Plenty of System Cache Memory and Fast Cache SSDs?
If you are experiencing high write latencies in VMs when using an EMC Unity Hybrid array, it could be because the caching and tiering solutions in Unity don’t cache random small block writes, and your applications might be generating large volumes of such storage IO.
The big difference between the two is that VSA caches only 2GB of reads from the Master VM1,2. VirtuCache caches reads + writes from all server & desktop VMs, and it can cache to TBs of in-host SSD/RAM, so that all storage IO is serviced from in-host cache.
More details in the table below.
In-VMware Host Caching – Datrium’s Appliance Specific Host Cache Versus Virtunet’s Host Cache for Any Storage.
March 7, 2019:
As it relates to storage, genome sequencing workflow has two requirements.
Need for cheap ($/GB) Petabyte scale storage.
Need for faster processing of Genome files under analysis, many of which are a few hundred GB in size.
April 15, 2020:
City of Mountain View is using VirtuCache to improve the performance of Netapp's Ontap Select storage software. They were one of our first customers to upgrade to ESXi 7.0 and so they had to upgrade VirtuCache as well.
We announced General Availability of VirtuCache for ESXi 7 within 2 weeks of VMware's ESXi 7 release date.