Thin Provisioning is a technology employed by storage products for optimized resource utilization. Under a Thin provisioned scheme, a disk is created with the specified size by pre-allocating none or partial storage space for it. The underlying blocks are allocated as-and-when a write is issued by the host to the disk. This technology improves the utilization of the storage subsystem when space is pooled across multiple disks. To derive full value of thin provisioning, it is important for the host to release disk blocks that are not being used anymore.