Rolling Back a Snapshot

Prerequisites

• At least one snapshot has been created on the storage system and is in the Activated state.
• Host services have been stopped, for the purpose of ensuring data consistency.
• If the source LUN of a snapshot is the primary LUN of a remote replication pair, you can roll back the snapshot only after the status of the remote replication pair changes to Split.
• If the source LUN of a snapshot is the local LUN or remote LUN of a HyperMetro pair, you can roll back the snapshot only after the HyperMetro pair is paused.

Precautions

• If a source LUN has multiple snapshots, you can roll back only one snapshot at a time.
• You cannot roll back a snapshot if its source LUN is the secondary LUN of a remote replication pair.
• You cannot roll back a snapshot if its source LUN is used as the primary LUN of a clone pair.
• You can roll back a snapshot if its source LUN is used as the secondary LUN of a clone pair, the pair's Pair Running Status is Split, and the pair's Data Status is Consistent or Reverse inconsistent.
• You cannot roll back a snapshot if it or its source LUN is being expanded.
• If a snapshot to be rolled back and its source LUN vary in capacity, a message will display, asking you to perform capacity expansion to maintain their capacities identical before a rollback.
  • For details about how to expand a source LUN, see the Basic Storage Service Configuration Guide for Block specific to your product model.
  • For details about how to expand a snapshot, see Expanding a Snapshot.
• If the source LUN of a snapshot is a thin LUN that acts as the remote LUN of a HyperMetro pair, you are advised not to roll back the snapshot before the initial synchronization between the two LUNs in the HyperMetro pair is complete, thereby preventing data inconsistency.
• If the source LUN of a snapshot is the primary LUN of a clone pair, you cannot add a secondary LUN during the rollback.

Procedure

1. Log in to DeviceManager.
2. Choose Data Protection > Snapshot > LUN.
3. In the function pane, select the snapshot you want to roll back and choose More > Start Rollback on the menu bar.

   The Roll Back Snapshot dialog box is displayed.

4. Set the snapshot rollback speed.
   1. From the Rollback Speed drop-down list, select a rollback speed. Available speeds are Low, Medium, High, and Highest.
      • When the service load on the storage system is heavy, set the rollback speed to Low or Medium.
      • When the service load on the storage system is light, set the rollback speed to High or Highest.
      • Low: When the speed is set to low, the rollback will take a long time. This value is applicable when the service load is heavy. Without considering other operations' impacts on the storage system, the speed is normally from 0 to 5 MB/s.
      • Medium: When the speed is set to medium, the rollback will take a relatively short period. This value is applicable when the service load is relatively heavy. Without considering other operations' impacts on the storage system, the speed is normally from 10 to 20 MB/s.
      • High: When the speed is set to high, the rollback will take a short period. This value is applicable when the service load is relatively light. Without considering other operations' impacts on the storage system, the speed is normally from 50 to 70 MB/s.
      • Highest: When the speed is set to highest, the rollback will take the shortest period. This value is applicable when the service load is light. Without considering other operations' impacts on the storage system, the speed is normally above 100 MB/s.
   2. Click OK.

      The security alert dialog box is displayed.

5. Roll back the snapshot.
   1. Confirm the information in the dialog box, select I have read and understand the consequences associated with performing this operation, and click OK.

      The Execution Result dialog box is displayed, indicating that the operation succeeded.

   2. Click Close.