If you are looking for solution with PowerCLI, take a look at Re: List VMFS version and blocksize of all Datastores
André
If you are looking for solution with PowerCLI, take a look at Re: List VMFS version and blocksize of all Datastores
André
The block size is defined when the VMFS-3 Datastore is created - to change you have remove the VMFS datastore and rebuild with the new block size-
From vSphere CLient, get a host, Configuration tab, Storage, select a DataStore and get BlockSize in "Datastore Details" pane as "Formatting --> Block Size"