6.5.1

Table Of Contents
VMFS6 processes the unmap request from the guest OS only when the space to reclaim equals 1 MB or
is a multiple of 1 MB. If the space is less than 1 MB or is not aligned to 1 MB, the unmap requests are not
processed.
Space Reclamation for VMFS5 Virtual Machines
Typically, the unmap command that generates from the guest operation system on VMFS5 cannot be
passed directly to the array. You must run the esxcli storage vmfs unmap command to trigger
unmaps for the array.
However, for a limited number of the guest operating systems, VMFS5 supports the automatic space
reclamation requests.
To send the unmap requests from the guest operating system to the array, the virtual machine must meet
the following prerequisites:
n
The virtual disk must be thin-provisioned.
n
Virtual machine hardware must be of version 11 (ESXi 6.0) or later.
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The advanced setting EnableBlockDelete must be set to 1.
n
The guest operating system must be able to identify the virtual disk as thin.
vSphere Storage
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