Administrator Guide

Data Reduction Options for VVols
You can specify data reduction options when creating storage containers. These options are advertised (made available) to the
VMware administrator during VM Storage Profile creation.
When you use Storage Manager to create storage containers, you can optionally set these data reduction options:
● Deduplication Allowed
● Compression Allowed
Specifying one or both of these options indicates the data reduction preferences for VMs that are then created.
You can also specify options for Data Reduction Input:
● None
● Compression
● Deduplication with Compression
These options are presented as checkboxes on the Create Storage Container wizard.
NOTE: Even if the Compression Allowed and Deduplication Allowed checkboxes are selected, selecting the None
profile option results in no action being taken.
You can also select the Default Data Reduction Profile, if one has been specified using the User Preferences.
After a storage administrator creates a storage container with data reduction options specified, these options are advertised
(shown as being selected) on the VM Storage Profile wizard when a VMware administrator creates a storage profile. If you edit
the storage container’s Data Reduction option, you also change the advertised capabilities that are visible in the VM Storage
Profile.
For information about using VM Storage Profiles, see the VMware vCenter documentation.
Factors That Affect Data Reduction Operation
When a new virtual volume is created, it can use any Data Reduction type supported by the storage container. The preference
for the Data Reduction type on the virtual volume is influenced by either:
● The VM Storage Profile, if one is established and used
● The default Data Reduction Profile set for the storage center
The following factors affect how Data Reduction options are applied:
● If no VM Storage Policy is chosen, the Data Reduction type defaults to the value selected by the Default Data Reduction
Profile.
● Editing an existing storage container’s properties to change the value of the Default Data Reduction Profile does not
affect existing virtual volumes. This change applies only to new volumes created afterward.
● If an existing volume has an enabled feature that is now disabled, the volume itself does not change. In the VM Storage
Profile, the volume would now appear to be noncompliant. To bring the volume back into compliance, you can apply a
compliant policy to the volume.
NOTE: The VM Storage Profile takes precedence when compatible storage exists.
NOTE: VM storage policies are applied only to data and config VVols and not to memory and swap VVols.
NOTE: When modifying VM storage policies especially for compression and deduplication, apply the VMware administrator
policies to all volumes associated with VM. If these same changes are not applied to all volumes, some portion of the VM
could be compressed while other portions could be uncompressed.
NOTE: The advertised capabilities only apply to VVols datastores and are not supported on legacy VMFS datastores.
NOTE: Any change to a storage container's Data Reduction profile might cause future fast cloned VMs to be created with
mismatched Data Reduction profiles for the config and data VVols. A fast clone VM shares history with the VM from which
it was created. Hence its data VVols inherit the settings of the data VVols of the original VM. There is another side effect of
this shared history — if a user applies a VM Storage Policy to the original VM, the same changes apply to the data VVols of
the fast clone VM and conversely.
180 Managing Virtual Volumes With Storage Manager