Your customer set up a SnapMirror synchronous relationship between two sites. They want to convert it to a SnapMirror active sync configuration for…

The process of changing a SnapMirror Synchronous (SM-S) relationship to a SnapMirror active sync (also known as SnapMirror Business Continuity or SM-BC) configuration is not a direct conversion. The existing SM-S relationship must be deleted and a new SM-BC relationship created.

When the SM-S relationship is deleted, the destination volumes transition from a data protection (DP) state to a read-write (RW) state, and the LUNs within them become online. Before you can create the new SM-BC relationship using these volumes, you must ensure no hosts are actively accessing them. Therefore, any LUNs that might have been mapped on the destination (for example, during a DR test) must be unmapped. This ensures that the SM-BC creation process can take exclusive control of the LUNs to manage their state and I/O across both sites without interference.

A. Changing the SnapMirror policy to Continuous is an action performed during the creation of the new SM-BC relationship, not a prerequisite step before the process begins.

B. Destroying the destination volumes is incorrect. This would discard the already replicated data, forcing a time-consuming and network-intensive re-synchronization for the new relationship.

D. Stopping the destination SVM is incorrect. The destination SVM must be running and properly configured to establish peering and create the new SnapMirror active sync relationship.

1. NetApp ONTAP 9.12 Documentation, Data protection and disaster recovery management, "SnapMirror Synchronous overview": This document clarifies that for SM-S, "The destination volume is not accessible to clients." When the relationship is deleted, the volume state changes. The snapmirror delete command documentation confirms that after deletion, a DP volume becomes read-write.

2. NetApp Technical Report TR-4732, "SnapMirror Business Continuity: Architecture and Best Practices": Section 3, "Deployment," outlines the requirements for creating an SM-BC relationship. It states, "Migration from an existing SnapMirror relationship to SnapMirror Business Continuity is not supported. You must create a new SnapMirror Business Continuity relationship." This supports the procedural requirement to delete the old relationship first. The creation process requires ONTAP to manage the LUNs, which is not possible if they are actively mapped to a host initiator.

3. NetApp ONTAP 9 Command Reference, snapmirror delete: The manual page for this command states: "When a SnapMirror relationship with a DP destination volume is deleted, the destination volume is brought online in a read-write state." This confirms that the LUNs on the destination become accessible and could potentially be mapped, necessitating the unmapping action before creating a new relationship.