Hello,   FYI:  You put this request in the Equallogic support forum, not Compellent.  However, the process is the same regardless of storage type.  No block storage OS can automatically determine what blocks are no longer in use on its own.  Only the owner of the filesystem knows that.  In the case of VMware ESXi,  they do not send the command to UNMAP a block on the fly.  It must be done at the CLI using the process you included.   Regards,   Don 
Guys,  I am new to Compellent and I am in a new role hat uses it exclusively  SC8000 v6.4.5  We use a lot of RDMs here but  would it be worth running these commands against our VMFS datastores and is it still needed with version 6.4.5? Issue UNMAP command against VMFS datastore (manually) The actual space reclamation command is as follows. This writes a “balloon file” to the top blocks of the datastore to persuade the SAN into relinquishing free space I there is space tied up i would like to free it up, devs create and delete VMs on the regular and I am not sure if this is being done yet and I would like to propose doing it?  There is no chance of corrupting data on the datastore?
UNMAP ESXi5.1 Compellent FC Array