Knowledge Center

Recovery

In the Recovery page, you can recover data from local snapshots, or perform a failover for your shared folder/iSCSI LUN to one of the destinations.

When you recover from a snapshot, you can not only have the entire shared folder/iSCSI LUN to be overwritten by the taken snapshot, but also clone a snapshot without additional storage consumption to test and verify if the snapshot works well when being restored. Moreover, you can conduct a file-level or folder-level recovery by using any file protocols (e.g., File Station, and Previous Versions in Windows File Explorer). To grant users the access to shared folder snapshots, please enable Make snapshot visible for each shared folder, and users can thus access the snapshots via File Station or Windows File Explorer.

When the source of a replication task fails to deliver normal service, you can perform recovery by failing over the shared folder/iSCSI LUNs to the destination. When you perform a failover to the shared folders/iSCSI LUNs, the replicated shared folders/iSCSI LUNs will change the state from read-only into writable on the original destination, taking over the workload of the original source. You can redirect all of your clients and applications to access the new hostname/IP address of the original destination. After the original source resumes normal operations, you can re-protect your shared folder/iSCSI LUNs to determine the new source and destination of the replication task. Moreover, you can specify to re-protect your data from either source or destination. Before you perform the re-protect operation, all replication tasks between the source and destination will be paused. When both the source and destination work normally, you can perform a switchover for your replication task to exchange their roles to meet your need of data storage.

To ensure successful recovery of your services and applications, shared folders and iSCSI LUNs, you can perform a test failover to clone a writable shared folder/iSCSI LUN on the destination (as the simulated new source) where you can conduct essential tests to check if this clone works well. For example, you can test if the virtual machines hosted by the tested iSCSI LUN can successfully launch their operating system.

Shared Folder

To restore individual files/folders in a shared folder:

  1. Select the shared folder you wish to restore.
  2. Click Recover.
  3. Select a snapshot version you wish to restore from.
  4. Click Browse, and copy the files/folders you would like to restore to the destination.

To restore a shared folder:

  1. Select the shared folder you wish to restore.
  2. Click Recover.
  3. Select a snapshot version you wish to restore from.
  4. Click Action, and select Restore in-place from the drop-down list.
  5. You will see a confirmation message. Click Yes to confirm the action.

To clone a snapshot to a new shared folder:

  1. Select the shared folder you wish to clone.
  2. Click Recover.
  3. Select a snapshot version you wish to clone to a new shared folder.
  4. Click Action, and select Clone with a new name from the drop-down list.
  5. You will be redirected to the Clone page in Control Panel > Shared Folder > Create. Enter the name of the cloned shared folder and click OK to finish.

Note:

  • Restoring and cloning shared folders are not available when a volume has less than 100 MB of free space.
  • Neither type of recovery is available for mounted encrypted shared folders.
  • The shared folder "homes" cannot be restored.
  • The cloned shared folders cannot be encrypted.
  • If a snapshot is taken when transfer of any files is still in progress, the data consistency will not be guaranteed.
  • On the replication source, mounted encrypted shared folders cannot be recovered.
  • On the replication destination, Clone with a new name is not available for mounted encrypted shared folders.
  • On the replication destination, Restore in-place is not available for either shared folders or encrypted shared folders.
  • Clone with a new name is not available for encrypted shared folders in DSM versions earlier than DSM 6.2.

To switch over the replication of shared folder:

  1. Select the replicated shared folder you wish to switch over.
  2. Click Action > Switchover.
  3. Select the new destination if there are multiple replication tasks of the shared folder.
  4. Click Switchover to start the action.

Note:

  • You must unmount the replicated encrypted shared folder before switching it over.
  • You cannot perform a switchover to a replication task created for the "homes" shared folder.

To fail over a replication of shared folder:

  1. Select the replicated shared folder you wish to fail over on the destination.
  2. Click Action > Failover.
  3. Select the version of snapshot to restore.
  4. Click Failover to start the action.

Note:

  • You can only initiate a failover upon failure of the source.
  • You must unmount the replicated encrypted shared folder before failing it over.
  • You cannot perform a failover to a replication task created for the "homes" shared folder.

To perform a forced failover for a replication of shared folder:

  1. Select the replicated shared folder for which you wish to perform a forced failover on the destination.
  2. Click Action > Forced Failover.
  3. Select the version of snapshot to restore.
  4. Click Forced Failover to start the action.

Note:

  • You run the risk of data loss when initiating a forced failover.
  • You must unmount the replicated encrypted shared folder before forcing its failover.
  • You cannot perform a forced failover to a replication task created for the "homes" shared folder.

To re-protect the replication of a shared folder:

When being failed over to the destination, the replication task will stop syncing data between the source and destination. You will need to re-protect the replication task after the original source is recovered.

  1. Select the failed over shared folder you wish to re-protect.
  2. Click Action > Re-protect.
  3. Select the new source.
  4. Select the new destination if there are multiple replication tasks of the shared folder.
  5. Select to re-protect with the data on either source or destination.
  6. Click Re-protect to start the action.

Note:

  • The data of the replicated shared folder existing on the new destination will be overwritten by that on the new source.
  • To re-protect an encrypted shared folder with the data different from those on the new source, you must unmount the encrypted shared folder first.

To perform a test failover for a replicated shared folder:

  1. Select the replicated shared folder you wish to test.
  2. Click Action > Test Failover.
  3. Select the Test Server if there are multiple replication tasks of the shared folder.
  4. Enter the Name for Test Failover of the shared folder, and select a snapshot version to test.
  5. Click Test Failover to start the action.

Note:

  • Performing a switchover/failover of a replication will clean up its test failover.
  • You cannot create a replication task for a test failover shared folder.
  • Test failover function is not available for encrypted shared folders in DSM versions earlier than DSM 6.2.
  • You cannot perform a test failover to a replication task created for the "homes" shared folder.

To clean up test failover for a replicated shared folder:

  1. Select the replicated shared folder of which you wish to clean up test failover.
  2. Click Action > Cleanup Test Failover.
  3. Tick the checkbox for the test failover if you wish to keep the shared folder created for the test failover.
  4. Click Cleanup Test Failover to start the action.

iSCSI LUN

For the best user experience, it is recommended to install the same version of Snapshot Replication on your source server and destination server.

To restore an iSCSI LUN:

  1. Select the iSCSI LUN you wish to restore.
  2. Click Recover.
  3. Select the snapshot version you wish to restore from.
  4. Click Action, and select Restore in-place from the drop-down list.
  5. You will see a confirmation message. Click Yes to confirm the action.

To clone a snapshot to a new iSCSI LUN:

  1. Select the iSCSI LUN you wish to clone.
  2. Click Recover.
  3. Select the snapshot version you wish to clone to a new iSCSI LUN.
  4. Click Action, and select Clone with a new name from the drop-down list.
  5. You will be redirected to the Clone page in iSCSI Manager > Snapshot > Clone. Enter the name of the cloned iSCSI LUN and click OK to finish.

    6. Note: iSCSI Manager is supported from DSM 6.2 onwards. Corresponding functions in previous DSM versions can be found at Storage Manager > iSCSI LUN.

Note:

  • Restoring and cloning iSCSI LUNs are not available when a volume has less than 1GB of free space.
  • If a snapshot is taken when transfer of any files is still in progress, the data consistency will not be guaranteed.
  • The snapshots of the iSCSI LUNs used by Cinder cannot be restored in-place. You can only Clone with a new name for such snapshots, and they will be cloned to general Advanced LUNs after the operation. For more information, please refer to DSM Help > iSCSI Manager > iSCSI LUN. For DSM versions earlier than DSM 6.2, please refer to DSM Help > Storage Manager > iSCSI LUN.
  • If an iSCSI LUN is used as the destination of replication, it cannot be restored by using Restore in-place.

To switch over the replication of iSCSI LUN:

  1. Select the replicated iSCSI LUN you wish to switch over.
  2. Click Action > Switchover.
  3. Select the new destination if there are multiple replication tasks of the iSCSI LUN.
  4. Click Switchover to start the action.

Note:

  • The volume where the iSCSI LUN is located must have more than 1GB of free space if you wish to switch over the replication.

To fail over a replication of iSCSI LUN:

  1. Select the replicated iSCSI LUN you wish to fail over on the destination.
  2. Click Action > Failover.
  3. Select the version of snapshot to restore.
  4. Click Failover to start the action.

Note:

  • You can only initiate a failover upon failure of the source.

To perform a forced failover for a replication of iSCSI LUN:

  1. Select the replicated iSCSI LUN for which you wish to perform a forced failover on the destination.
  2. Click Action > Forced Failover.
  3. Select the version of snapshot to restore.
  4. Click Forced Failover to start the action.

Note:

  • You run the risk of data loss when initiating a forced failover.

To re-protect the replication of an iSCSI LUN:

When being failed over to the destination, the replication task will stop syncing data between the source and destination. You will need to re-protect the replication task after the original source is recovered.

  1. Select the failed over iSCSI LUN you wish to re-protect.
  2. Click Action > Re-protect.
  3. Select the new source.
  4. Select the new destination if there are multiple replication tasks of the iSCSI LUN.
  5. Select to re-protect with the data on either source or destination.
  6. Click Re-protect to start the action.

Note:

  • The data of the replicated iSCSI LUN existing on the new destination will be overwritten by that on the new source.

To perform a test failover for a replicated iSCSI LUN:

  1. Select the replicated iSCSI LUN you wish to test.
  2. Click Action > Test Failover.
  3. Select the Test Server if there are multiple replication tasks of the iSCSI LUN.
  4. Enter the Name for Test Failover of the iSCSI LUN, and select a snapshot version to test.
  5. Click Test Failover to start the action.

Note:

  • Performing a switchover/failover of a replication will clean up its test failover.
  • You cannot create a replication task for a test failover iSCSI LUN.

To clean up test failover for a replicated iSCSI LUN:

  1. Select the replicated iSCSI LUN of which you wish to clean up test failover.
  2. Click Action > Cleanup Test Failover.
  3. Tick the checkbox for the test failover if you wish to keep the iSCSI LUN created for the test failover.
  4. Click Cleanup Test Failover to start the action.

Multiple Selection

To select more than one shared folder/iSCSI LUN simultaneously:

  1. Click on one of the items you wish to select first.
  2. Press and hold Ctrl or Shift to select more items.

Note:

  • All the selected items must be replicated between the same source and destination.
  • If some of the multi-selected items are not replicated between the same source and destination with the first selected item, they will be deselected automatically.
Shared Folder
iSCSI LUN
Multiple Selection