6.7

Table Of Contents
Space
Reclamation
Priority Description Configuration
None Disables the unmap operations for the datastore. vSphere Client
esxcli command
Low (default) Sends the unmap command at a less frequent
rate, 25–50 MB per second.
vSphere Client
esxcli command
Medium Sends the command at a rate twice faster than the
low rate, 50–100 MB per second.
esxcli command
High Sends the command at a rate three times faster
than the low rate, over 100 MB per second.
esxcli command
Note The ESXi host of version 6.5 does not recognize the medium and
high priority rates. If you migrate the VMs to the host version 6.5, the rate
defaults to low.
After you enable space reclamation, the VMFS6 datastore can start releasing the blocks of unused space
only when it has at least one open file. This condition can be fulfilled when, for example, you power on
one of the VMs on the datastore.
Manual Reclamation of Free Space on VMFS5 Datastore
VMFS5 and earlier file systems do not unmap free space automatically, but you can use the esxcli
storage vmfs unmap command to reclaim space manually. When you use the command, keep in mind
that it might send many unmap requests at a time. This action can lock some of the resources during the
operation.
Configure Space Reclamation for a VMFS6 Datastore
When you create a VMFS6 datastore, you can modify the default parameters for automatic space
reclamation.
At the VMFS6 datastore creation time, the only available method for the space reclamation is priority. To
use the fixed method, edit the space reclamation settings of the existing datastore.
Procedure
1 In the vSphere Client object navigator, browse to a host, a cluster, or a data center.
2 From the right-click menu, select Storage > New Datastore.
3 Follow the steps required to create a VMFS6 datastore.
vSphere Storage
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