Can someone tell me if EMC has offically "documented" that they suppport "thin on thin" luns from the VMAX to ESX hosts?  Last time I checked with EMC during the deployment of VMAX-20s for my past customer (2011-2012) EMC said verbally "We'll support it, but we don't recommend it". I know there are changes to VMware with VAAI such that issues of running out of space is less likely, I still haven't been able to find any WRITTEN documentation from EMC saying "Yes, thin on thin is approved by EMC".

Not trying to start a storm here, I just know there are possible issues with using thin on thin.  You either do it from the array side or ESX side but not usually both.

Thoughts?