Performing a switchback

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After you heal the MetroCluster configuration, you can perform the MetroCluster switchback operation. The MetroCluster switchback operation returns the configuration to its normal operating state, with the sync-source storage virtual machines (SVMs) on the disaster site active and serving data from the local disk pools.

  • The disaster cluster must have successfully switched over to the surviving cluster.

  • Healing must have been performed on the data and root aggregates.

  • The surviving cluster nodes must not be in the HA failover state (all nodes must be up and running for each HA pair).

  • The disaster site controller modules must be completely booted and not in the HA takeover mode.

  • The root aggregate must be mirrored.

  • The Inter-Switch Links (ISLs) must be online.

  • Any required licenses must be installed on the system.

    1. Confirm that all nodes are in the enabled state: metrocluster node show

      The following example displays the nodes that are in the enabled state:

      cluster_B::>  metrocluster node show
      
      DR                        Configuration  DR
      Group Cluster Node        State          Mirroring Mode
      ----- ------- ----------- -------------- --------- --------------------
      1     cluster_A
                    node_A_1    configured     enabled   heal roots completed
                    node_A_2    configured     enabled   heal roots completed
            cluster_B
                    node_B_1    configured     enabled   waiting for switchback recovery
                    node_B_2    configured     enabled   waiting for switchback recovery
      4 entries were displayed.
    2. Confirm that resynchronization is complete on all SVMs: metrocluster vserver show

    3. Verify that any automatic LIF migrations being performed by the healing operations have been successfully completed: metrocluster check lif show

    4. Perform the switchback by running the metrocluster switchback command from any node in the surviving cluster.

    5. Check the progress of the switchback operation: metrocluster show

      The switchback operation is still in progress when the output displays waiting-for-switchback:

      cluster_B::> metrocluster show
      Cluster                   Entry Name          State
      ------------------------- ------------------- -----------
       Local: cluster_B         Configuration state configured
                                Mode                switchover
                                AUSO Failure Domain -
      Remote: cluster_A         Configuration state configured
                                Mode                waiting-for-switchback
                                AUSO Failure Domain -

      The switchback operation is complete when the output displays normal:

      cluster_B::> metrocluster show
      Cluster                   Entry Name          State
      ------------------------- ------------------- -----------
       Local: cluster_B         Configuration state configured
                                Mode                normal
                                AUSO Failure Domain -
      Remote: cluster_A         Configuration state configured
                                Mode                normal
                                AUSO Failure Domain -

      If a switchback takes a long time to finish, you can check on the status of in-progress baselines by using the metrocluster config-replication resync-status show command. This command is at the advanced privilege level.

    6. Reestablish any SnapMirror or SnapVault configurations.

      In ONTAP 8.3, you need to manually reestablish a lost SnapMirror configuration after a MetroCluster switchback operation. In ONTAP 9.0 and later, the relationship is reestablished automatically.