i agree with kslish,
ILIO Atlantis is the way to go. Even the older version with diskback is solid.
been using this method for a few years now.
non persistant vms with linked clones sitting on a ILIO-Write-cache store and all replicas sitting on a ILIO-Read- cache store does the job.
youll notice your read /write to the Low end budget san or high end san will drop dramatically.
improvement all round.