Modifying Snapshot Settings

There are three snapshot settings for a volume:

• Snapshot reserve size
• Low-snapshot space warning threshold
• Policy to follow when snapshot space is exceeded

When creating a volume, the default snapshot settings are the group-wide settings, as described in Creating Volumes. You can change the snapshot settings for an existing volume, as needed.

To modify the snapshot settings for a volume, click:

Volumes > volume_name > Modify snapshot settings

The Modify Snapshot Settings dialog box appears (Figure 1: Modify Snapshot Settings ).

Figure 1: Modify Snapshot Settings

You can change the following settings:

• Snapshot reserve. Specify the amount of space, as a percentage of the volume reserve, to reserve for snapshots of the volume.

When you change the snapshot reserve, the values in the pool space table shown in Figure 1: Modify Snapshot Settings are updated:

• Volume reserve. Pool space allocated to the volume.
• Snapshot reserve. Pool space reserved for snapshots of the volume.
• Free pool space. Unused pool space.

If increasing the snapshot reserve will exceed the capacity of the pool, the new free pool space cell will turn red.

Note that if you decrease the snapshot reserve below the amount of space that is currently holding snapshot data, the snapshot space recovery policy will be enforced, as described below.

• Snapshot space recovery policy. Select the action to take when the reserved snapshot space has been exceeded, either delete oldest snapshot or put the volume and its snapshots offline. If a snapshot has active iSCSI connections, the connections will be terminated before the snapshot is deleted or the volume and its snapshots are set offline.
• Snapshot space warning level. Change the warning level by moving the slider in the Modify Snapshot Settings dialog box (Figure 1: Modify Snapshot Settings ). When the in-use snapshot reserve reaches the value specified by the warning level (set as a percentage of the snapshot reserve), an alarm is generated. For example, if a volume is 200 MB with 100% of the volume size reserved for snapshots, and the warning level is 90%, a warning will be generated when in-use snapshot reserve reaches 180 MB.

When you have completed the changes to the snapshot settings, click OK.