One challenge inherent in storage arrays that present thin provisioned volumes is how the various operating systems that use those volumes indicate that data has been deleted. This is referred to as Dead Space Reclamation and is provided by one of two techniques: SSD Trim or SCSI Unmap.
This process enables you to reclaim blocks of thin-provisioned LUNs by telling the array that specific blocks are obsolete. Most legacy operating systems inherently do not provide this capability, so special attention needs to be paid if a Host performs large delete operations without rewriting new data into the deleted space. Most current operating systems, such as ESX 5.x+, Windows 2012, 2012 R2, 2016, and RedHat Enterprise Linux 6 provide this functionality.