Migrating Data from the Same-City DR Center Back to Active-Active Data Centers

Prerequisites

• LUN-based protection policies and recovery plans have been configured for other applications.
• For protected groups that use asynchronous remote replication, the DR center has at least one copy of intact service data.

Context

Services are migrated from active-active data centers to the DR center due to a recoverable fault such as an unexpected power failure. After the active-active data centers recover from the fault, you must synchronize data generated during the fault from the same-city DR center to the active-active data centers and migrate services back to the active-active data centers. Figure 1 shows the state of data replication between storage arrays before failback.

Figure 1 Data replication before failback

Procedure

• In HyperMetro (SAN) and asynchronous replication (SAN) scenarios, you can use eReplication to migrate back services as follows:
  1. Check the environment before starting the reprotection.
     1. Log in to a service host in an HyperMetro data center and stop services.
     2. Suspend HyperMetro pairs that are at active end of storage arrays in the HyperMetro data centers.
        Figure 2 shows the state of data replication between storage arrays before the planned migration.

        Figure 2 Data replication before the planned migration
        
  2. Perform reprotection to protect services switched to the same-city DR center.

     After the fault recovery is complete, the application system is working at the same-city DR center and protection groups become Invalid. You must perform reprotection to recover the replication status and synchronize data from the same-city DR center to the active-active data center.

     

     To ensure the normal running of protected groups and recovery plans after reprotection, the system automatically clears protected and recovered configurations, including startup configurations of protection policies and recovery plans, self-defined execution scripts, and self-defined execution steps. In addition, reconfiguration of protection and recovery policies is recommended to ensure the continuity of DR services.

     1. On the menu bar, select Utilization > Data Restore.
     2. Select the recovery plan and click More > Reprotection on the Operation list.
     3. Carefully read the content in the Confirm dialog box that is displayed and click OK to confirm the information.
        

        If Save user configuration data is selected, self-defined protection policies and recovery settings, such as self-defined recovery steps, will be retained. Ensure that the configuration data has no adverse impact on service running after reprotection.

        Figure 3 shows the state of data replication between storage arrays after the reprotection.

        Figure 3 Data replication after the reprotection
        
  3. Test recovery plans and clear data generated during tests.

     Before services are migrated back, perform a DR test to verify data availability to ensure service failback success rate. After the test, clear test data to avoid failback failures caused by the test data. For details, see DR Testing.

  4. Perform planned migration.

     Migrate services back to the active-active data center. After the migration, check data and clear test data.

     

     You can select Synchronize HyperMetro to enable HyperMetro synchronization.

     Figure 4 shows the state of data replication between storage arrays after the planned migration.

     Figure 4 Data replication after the planned migration
     
  5. Perform reprotection again.

     After the planned migration is complete, application systems are working in HyperMetro data centers and protected groups become Invalid. To ensure that services migrated back to the original HyperMetro data centers can be recovered at the Same-city DR center after an event (planned or unplanned) happens, reprotection must be performed and the replication status from HyperMetro data centers to the Same-city DR center must be recovered to synchronize data generated at the HyperMetro data centers to the remote DR site and to ensure that services are protected. For details, see see 5 to 6 in Planned Migration from an Active-Active Data Center to the Same-City DR Center.

     Figure 5 shows the state of data replication between storage arrays after the reprotection.

     Figure 5 Data replication after the reprotection
     

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