The purpose of a MetroCluster switchback is to return storage and client access to the original disaster site (Site A) after a switchover event has been resolved. This planned procedure involves resynchronizing the data from the surviving site (Site B) back to the repaired original site. Once synchronization is complete, the aggregates are brought online at the original site, and client access is restored, returning the configuration to its normal, pre-disaster operational state. This ensures the system is again protected against a failure at the other site.

B. Delete mirrored aggregates: Switchback does not delete aggregates; it resynchronizes and brings the original mirrored aggregates back online at the primary site.

C. Disable synchronous replication: Switchback re-establishes and verifies synchronous replication (SyncMirror) to ensure the configuration is fully protected after the operation.

D. Restart storage controllers: While controller reboots are part of the overall process, the fundamental purpose is to restore service to the original site, not just restart hardware.

1. NetApp, "MetroCluster Management and Disaster Recovery Guide," Document Version 1.0, March 2023. In the "Overview of the switchback process" section, it states, "Switchback is the process of returning storage and client access to the original cluster after a disaster has been resolved."

2. NetApp, "TR-4705: NetApp MetroCluster Solution Architecture and Design," Published February 2023. Section "Switchback," page 41, describes switchback as the process to "return the configuration to normal operating condition."