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ONTAP MetroCluster

Performing a switchback

Contributors netapp-martyh netapp-ranuk NetAppZacharyWambold
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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 a simulated switchback to verify the system is ready: metrocluster switchback -simulate

    5. Check the configuration:

      metrocluster check run

      The command runs as a background job and might not be completed immediately.

      cluster_A::> metrocluster check run
The operation has been started and is running in the background. Wait for
it to complete and run "metrocluster check show" to view the results. To
check the status of the running metrocluster check operation, use the command,
"metrocluster operation history show -job-id 2245"
      cluster_A::> metrocluster check show
Last Checked On: 9/13/2018 20:41:37

Component           Result
------------------- ---------
nodes               ok
lifs                ok
config-replication  ok
aggregates          ok
clusters            ok
connections         ok
6 entries were displayed.

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

    7. 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.

    8. 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.