When VMFS datastores reside on thin-provisioned LUNs, you can use the vmkfstools -y to reclaim storage blocks resulting from deleting or moving files from the VMFS datastores.


You can use this command only if your storage vendor has tested this option with storage arrays and supports it. For information on how to verify whether the array supports this command, see the VMware knowledge base article at http://kb.vmware.com/kb/2014849.

Upgrade your host to ESXi 5.1.

Upgrade a datastore deployed on the thin-provisioned device to VMFS5.


On the ESXi Shell, change to the datastore directory by using the cd /vmfs/volumes/datastore_name command.


Reclaim a specified percentage of free capacity on the VMFS5 datastore for the thin-provisioned device by running vmkfstools -y %.

% is an integer between 1 and 99. It represents a percentage of VMFS free capacity to be reclaimed. The recommended value is 60.