Dell PowerVault ME5 Series Storage System CLI Reference Guide

Run this operation on the secondary system to move the replication set into "failed over" state. In this state, all scheduled or current replications of the replication set will cease and the secondary volume can be mapped and accessed for use (including rollback to the contents of any manually created or snapshot-history snapshot). Before performing failover, create a snapshot of the secondary volume to preserve the contents of the last replication, if snapshot history was not enabled.

This is a two-step operation that can restore the primary system using updates made to the secondary volume while the replication set was failed over to the secondary system.

First, run this operation on the secondary system. This will unmap the primary volume and the secondary volume and put the replication set in a temporary "failback-restore" state that permits a replication to go in the opposite direction: from the secondary volume to the primary volumes. Once the direction has been temporarily reversed, data from the secondary volume is replicated to the primary volume. At this point, data has been restored from the secondary system, but the replication set remains in a temporary state. Host mappings to either primary or secondary volumes are blocked when in this state. Replication snapshot history is suppressed while a failback-restore operation is in progress.

Second, run this operation on the primary system. This will reverse replication back to the normal direction: from the primary volume to the secondary volume. The temporary state imposed by the first step will be removed and the replication set will return to normal operation.

This restores the replication set to functioning as it did before the failover operation was performed. If the secondary volume was mapped while in "failed over" state, it will be unmapped. The direction of replication will not be changed from the original configuration and it will not automatically start a replication. After this operation completes, any updates to the secondary volume will remain. However, updates to the secondary volume will be discarded when the next replication request is completed.

This allows the replication set to return to normal operation, but with the replication roles reversed: the original primary volume becomes the secondary volume and the original secondary volume becomes the primary volume. The original primary volume becomes unmapped. The operation preserves any updates that may have been done to the original secondary volume while it was in "failed over" state, but does not automatically move these updates to the original primary volume. The next replication run will move these updates from the new primary volume to the new secondary volume, and will delete any changes made to the secondary (original primary) since the last replication.

operation failover|failback-restore|failback-no-restore|reverse

<replication-set-ID>

operation failover|failback-restore|failback-no-restore|reverse

Specifies the operation to perform, as described above.

failover: Moves the replication set into the "failed over" state required for performing a subsequent recovery operation. You must run this on the secondary system.

To use this option:

• The replication set can be in any state except "failed over."
• Peer communication can be online or offline.

failback-restore: Restores the primary system using updates made to secondary volumes while the replication set was failed over to the secondary system. You must run this first on the secondary system and then on the primary system. The system displays two confirmation prompts when run on the secondary system, and one confirmation prompt when run on the primary system.

To use this option on the secondary system:

• The replication set must be in the "failed over" state.
• Peers must be operational with both systems healthy and communicating.

When this option is run on the secondary system, a "reverse" replication is run.

To use this option on the primary system:

• The replication set must be ready, with the Failback In Progress field showing True.
• The primary and secondary volumes must be unmapped. (Unmapping occurs when this option runs on the secondary system. Mapping is not possible while Failback In Progress is True.)
• Replication from secondary volumes back to primary volumes must be complete.

failback-no-restore: Restores the replication set to functioning as it did before the failover operation was performed, without using updates made to the secondary volume while the replication set was failed over to the secondary system. You must run this on the secondary system.

To use this option:

• The replication set must be in the "failed over" state.
• Peers must be operational with both systems healthy and communicating.

reverse: Restores the replication set to normal operation but with the replication roles reversed. You must run this on the secondary system. The system displays two confirmation prompts.

To use this option:

• The replication set must be in the "failed over" state.
• Peers must be operational with both systems healthy and communicating.

<replication-set-ID>

The name or serial number of the replication set. A name that includes a space must be enclosed in double quotes.

# recover replication-set operation failover RS1

Replace the old data on the primary system with the current data on the secondary system. During this process preserve the data state of volumes on the primary systems to avoid risk of data loss. Follow these steps to replace the data:

1. On the primary system, snap local replication set volumes.
2. On the secondary system:
   1. Snap local replication set volumes.
   2. Run: recover replication-set operation failback-restore RS1
3. On the primary system:
   1. Confirm that the replication has completed by periodically running: show replication-sets RS1
   2. Run: recover replication-set operation failback-restore RS1
   3. Reestablish primary volume mappings.

create snapshots

map volume

show replication-sets