Rolling back a file system from a snapshot recovers the file system to the state that it was when the snapshot was created. For example, if a file system is corrupted due to an event such as a RAID controller crash, storage system component failure, or power loss, you can roll back to a previous snapshot of the file system.
A file system rollback from a snapshot requires the FS_RECOVER_FROM_SNAP licensed service on the managed server. For information about viewing licensed services, see Viewing license information.
Note: You can roll back a file system from a snapshot only when the configured number of preserved file system checkpoints were created since the snapshot was created. For example, if a file system is configured to preserve 128 checkpoints (the default), you can roll back the file system from a snapshot only after a minimum of 128 checkpoints are created. If less than the configured number of checkpoints are created, you can roll back from an earlier snapshot or from a checkpoint. To roll back from a checkpoint, use the fs-checkpoint-select command as described in the command reference for the storage platform.
The following file system rollback considerations apply:
- All snapshots are discarded after the rollback completes.
- No new snapshots occur until all previous snapshots are discarded.
- After you roll back a file system and mount it in read/write mode, you cannot undo the rollback or roll back again to a different snapshot or checkpoint.
The following types of rollbacks are available:
- Regular Rollback: The file system is rolled back to a selected snapshot. This option is also available for file systems that are object replication targets.
- Promote: The file system is rolled back to a selected snapshot and then is promoted to a live file system. This option is available only for file systems that are object replication targets.
- Demote: The file system is rolled back to a selected snapshot and is then demoted to an object replication target. This option is available only for file systems that are not object replication targets.