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Convert existing relationships to SM-BC relationships

Contributors netapp-ahibbard netapp-lenida

If you have an existing Synchronous SnapMirror relationship between a source and destination cluster, you can convert it to an SM-BC relationship. This allows you to associate the mirrored volumes with a consistency group, ensuring zero RPO across a multi-volume workload. Additionally, you can retain existing SnapMirror snapshots if you need to revert to a point in time prior to establishing the SM-BC relationship.

Before you begin
  • A zero RPO Synchronous SnapMirror relationship must exist between the primary and secondary cluster.

  • All LUNs on the destination volume must be unmapped before the zero RTO SnapMirror relationship can be created.

  • SM-BC only supports SAN protocols (not NFS/CIFS). Ensure no constituent of the consistency group is mounted for NAS access.

About this task
  • You must be a cluster and SVM administrator on the primary and secondary clusters.

  • You cannot convert zero RPO to zero RTO sync by changing the SnapMirror policy.

  • You must ensure the LUNs are unmapped before issuing the snapmirror create command.

    If existing LUNs on the secondary volume are mapped and the AutomatedFailover policy is configured, the snapmirror create will trigger an error.

Steps
  1. From the secondary cluster, perform a SnapMirror update on the existing relationship:

    destination::>snapmirror update -destination-path vs1_dst:vol1

  2. Verify that the SnapMirror update completed successfully:

    destination::>snapmirror show

  3. Quiesce each of the zero RPO synchronous relationships:

    destination::>snapmirror quiesce -destination-path vs1_dst:vol1

    destination::>snapmirror quiesce -destination-path vs1_dst:vol2

  4. Delete each of the zero RPO synchronous relationships:

    destination::>snapmirror delete -destination-path vs1_dst:vol1

    destination::>snapmirror delete -destination-path vs1_dst:vol2

  5. Release the source SnapMirror relationship but retain the common Snapshot copies:

    source::>snapmirror release -relationship-info-only true -destination-path vs1_dst:vol1

    source::>snapmirror release -relationship-info-only true -destination-path vs1_dst:vol2

  6. Create a group zero RTO Synchronous Snapmirror relationship:

    destination::> snapmirror create -source-path vs1_src:/cg/cg_src -destination-path vs1_dst:/cg/cg_dst -cg-item-mappings vol1:@vol1,vol2:@vol2 -policy AutomatedFailover

  7. Resynchronize the consistency group:

    destination::> snapmirror resync -destination-path vs1_dst:/cg/cg_dst

  8. Rescan host LUN I/O paths to restore all paths to the LUNs.