vSAN 6.7 Update 2 and later supports UNMAP commands that enable you to reclaim storage space that is mapped to deleted files in the vSAN Distributed File System (VDFS) created by the guest on the vSAN object.

Deleting or removing files and snapshots frees space within the file system. This free space is mapped to a storage device until the file system releases or unmaps it. vSAN supports reclamation of free space, which is also called the unmap operation. You can free storage space in the VDFS when you delete file shares and snapshots, consolidate file shares and snapshots, and so on. You can unmap storage space when you delete files or snapshots

Unmap capability is disabled by default. To enable unmap on a vSAN cluster, use the following RVC command:

vsan.unmap_support –enable

When you enable unmap on a vSAN cluster, you must power off and then power on all VMs. VMs must use virtual hardware version 13 or above to perform unmap operations.