6.7

Table Of Contents
The following thin provisioning status indicates that the storage device is thin-provisioned.
# esxcli storage core device list -d naa.XXXXXXXXXXXX4c
naa.XXXXXXXXXXXX4c
Display Name: XXXX Fibre Channel Disk(naa.XXXXXXXXXXXX4c)
Size: 20480
Device Type: Direct-Access
Multipath Plugin: NMP
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Thin Provisioning Status: yes
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An unknown status indicates that a storage device is thick.
Note Some storage systems present all devices as thin-provisioned no matter whether the devices are
thin or thick. Their thin provisioning status is always yes. For details, check with your storage vendor.
Storage Space Reclamation
ESXi supports the space reclamation command, also called SCSI unmap command, that originates from
a VMFS datastore or a VM guest operating system. The command helps thin-provisioned storage arrays
to reclaim unused space from the VMFS datastore and thin virtual disks on the datastore. The VMFS6
datastore can send the space reclamation command automatically. With the VMFS5 datastore, you can
manually reclaim storage space.
You free storage space inside the VMFS datastore when you delete or migrate the VM, consolidate a
snapshot, and so on. Inside the virtual machine, storage space is freed when you delete files on the thin
virtual disk. These operations leave blocks of unused space on the storage array. However, when the
array is not aware that the data was deleted from the blocks, the blocks remain allocated by the array
until the datastore releases them. VMFS uses the SCSI unmap command to indicate to the array that the
storage blocks contain deleted data, so that the array can unallocate these blocks.
vSphere Storage
VMware, Inc. 334