About Dell SC (Compellent).
The default Blocksize on storage side is 2MB (up to 4MB) which is more than 1MB so the automatic esxi vmfs 6.0 unmap feature cant work. If you have a Dell SC with SSDs only you can setup the array with 512KB blocksize. But even when using this blocksize iam not sure if the feature is working on the SC.
We run the unmap command trough a script from time to time.
Regards,
Joerg