Administrator Guide

• Volume reserve decreases to the amount of in-use space (or the minimum volume reserve, whichever is greater), and free
volume reserve becomes unreserved space.
• Snapshot reserve is adjusted, based on the new volume reserve. If necessary to preserve existing snapshots, the snapshot
reserve percentage is increased.
When you create a thin clone volume, it has the same reported size and contents as the template volume. If you mount the thin
clone, you can see the data that the thin clone shares with the template volume.
The group allocates only the minimum volume reserve when you rst create a thin clone. The group allocates additional space if you
specify snapshot reserve for the thin clone. As with a standard, thin-provisioned volume, as you write to a thin clone, the group
allocates more space and increases the volume reserve as needed.
In the Volume Status window for a thin clone volume, the Volume Space table shows the space utilization for the thin clone,
including the in-use space, which is the portion of volume reserve that is storing data unique to the thin clone. When you rst create
a thin clone, it has zero in-use space.
Also in the Volume Status window for a thin clone volume, the Shared Space table (appears only for thin clones) shows the amount
of space that is shared with the template volume and the unshared (in-use) space. As you write to the thin clone, unshared (in-use)
space increases. In some cases, when you write to a thin clone, shared space can decrease (for example, if you are overwriting
shared data).
Free space in the Shared Space table shows the amount of unwritten thin clone space (that is, the reported volume size minus the
combined shared space and unshared space). This space represents the amount of data you can write to the thin clone before you
need to increase its size. This value is the same as the value for “unreserved” space in the Volume Space table in the Volume Status
window for the template volume.
If you detach a thin clone, the resulting new standard volume has in-use space equal to the combined shared space and unshared
space, as shown in the Shared Space table in the Volume Status window.
Restrictions on Template Volumes and Thin Clones
With a few exceptions, all normal volume attributes and operations apply to template volumes and thin clones as specied in Table 37.
Template Volume and Thin Clone Restrictions.
Table 37. Template Volume and Thin Clone Restrictions
Attribute or Operation Restriction
Snapshots You cannot restore a template volume from a snapshot.
Thin provisioning You cannot disable thin provisioning on a template volume or thin clone.
Permissions You cannot set template volumes to read-write permission.
Volume collections You cannot include a template volume in a volume collection.
Scheduling operations You cannot schedule a snapshot or replication operation for a template volume.
RAID preference Thin clones inherit the RAID preference, if any, of the template volume.
Member binding Thin clones inherit the member binding setting, if any, of the template volume.
Cloning Cloning a template volume creates a new template volume with a new name and iSCSI target,
but the same reported size, pool, and contents as the original volume at the time of the cloning.
Cloning a thin clone creates a new thin clone with a new name and iSCSI target, but the same
reported size, pool, contents, and relationship to the template volume as the original thin clone
at the time of the cloning.
Resizing You cannot change the reported size of a template volume. However, you can change the thin-
provisioning settings.
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