Interoperability with Instant Clones

Instant Clones are a Horizon View feature that allows fast provisioning of VMs versus Full or Linked Clones. This is so because the Instant Cloned VMs share the memory and disk state of the parent VM.

VirtuCache supports Instant Clones. The only thing to watch out for is View Storage Accelerator (VSA), interchangeably referred to as Content Based Read Cache or CBRC by VMware. VSA allows shared blocks used by VMs to be cached to a maximum of 2GB of Host RAM. VSA is automatically turned on in Instant Clones. VirtuCache is a competing technology to VSA, and we don’t interoperate with VSA, also if you are using VirtuCache, you don’t need VSA. So you should disable VSA.

For reference purposes, here is how we compete with VSA.

1. VSA only caches common blocks used by VMs, so it would cache Replica VM blocks, Anti-Virus software and other applications that are common to VDI VMs. VirtuCache caches all frequently used data and all recent writes from and to VMs or ESXi hosts. So with VirtuCache you don’t need to use VSA. We woudl cache all the data that VSA caches plus a lot more.

2. VSA can cache to RAM only. Also it is capped to a maximum of 2GB of RAM only. VirtuCache can cache to any amount (TBs) of in-host RAM and/or SSD.