LUN clones can be replicated in optimized mode when you use SnapDrive for Windows to manage the SnapVault relationship. You need to keep certain conditions in mind when transferring LUN clones.
Consider the following requirements before using SnapVault
with LUN clones in optimized mode:
- SnapDrive for Windows only transfers optimized LUN clones supporting Microsoft Windows Volume Shadow Copy Services for TxF Recovery. Volume Shadow Copy Services helps create application-consistent Snapshot copies. SnapDrive for Windows automatically creates these Snapshot copies if the backup application requests TxF Recovery data during Snapshot creation. For more information on Volume Shadow Copy Services and TxF Recovery data, see the Microsoft documentation.
- SnapVault creates LUN clones on the secondary system if both the primary and secondary storage systems are running Data ONTAP 7.3 or later, and optimized transfers occur using SnapDrive for Windows.
- After the relationship has been handed off to SnapDrive for Windows, the relationship must be left there.
Attention: Do not run manual updates from the CLI. This might cause data corruption.
- When creating a SnapVault relationship, ensure that the SnapVault primary system does not contain any LUN clones.
- An initial LUN clone transfer requires the backing LUN and the cloned LUN to be in the same qtree.
- The backing Snapshot copy must exist on the secondary system. It can be missing on the primary system for optimized transfers.
- If the backing Snapshot copy is deleted on the secondary storage system, the transfer of the backup Snapshot copy fails.
If the backing Snapshot copy is deleted on the primary system, but exists on the secondary system, the transfer succeeds.
- The backing Snapshot copies on the secondary system are locked after the backup Snapshot copy is transferred. To delete a backing Snapshot copy, you should first delete any backup Snapshot copy that depends on it. You can run the lun snap usage command to find the backup Snapshot copy.
- During a restore operation, the backing Snapshot copy must be on the primary storage system before the backup Snapshot copy can be transferred. If the backing Snapshot copy already exists on the primary system, there is no need to transfer it again.
- If you have a SnapVault transfer followed by a volume SnapMirror cascade, you should not run volume SnapMirror updates while backing Snapshot copies are being transferred. This might cause SnapVault to use a sub-optimal backing Snapshot copy when the LUN clones are created. No data corruption is possible, but extra Snapshot copies might be locked.
- You should not create Snapshot copies manually when backing Snapshot copies are being transferred.
Note: If SnapDrive for Windows uses the SnapVault relationship running Data ONTAP 7.3 for Volume Shadow Copy Service-based backup, you should not revert to a release earlier than Data ONTAP 7.3.
For more details on how to transfer Volume Shadow Copy Service-based Snapshot copies
using SnapDrive for Windows
, see the SnapDrive for Windows Installation and Administration Guide