Restoring the Mirror Relationship

If the primary datacenter comes back online, the administrator can re-establish the mirror relationship between the original read-write volume in the primary datacenter and the promoted read-write volume in the secondary datacenter.

Note that the two read-write volumes will have different data, since data was written to the promoted mirror while the original source volume was down. The original source volume might also have different data that was written after the last mirror operation, but before the cluster went down. The administrator must decide which data to keep and use as the source.


Some data loss is inevitable in a disaster recovery scenario. To minimize potential data loss, use mirrors to provide a synchronized copy of each volume with critical data, and in the event of discrepancies, decide which data to preserve based on your company's policies.

The following sections provide information about how to restore the mirror relationship: