DR

If the production center malfunctions, use the DR center to take over services from the production center. After the production center is recovered, switch the services back to the production center.

The following introduces operations on a remote replication consistency group. Operations on a remote replication pair are similar.

If a disaster occurs in the production center, perform the following operations for the DR center to take over services:

1. Perform splitting operations on the storage system in the DR center.

   If the splitting fails, it may be caused by a replication link fault or a failure on the storage system in the production center. A splitting failure does not affect subsequent operations.

2. Disable secondary resource protection on the DR storage system.

3. Map the secondary LUN to the standby host.
   • Be aware that you cannot map primary and secondary LUNs to a same host; otherwise, a conflict may occur on the host, resulting in service interruption.
   • If the secondary LUN has already been mapped to the secondary host and the latest data cannot be accessed due to the host cache, cancel the mapping relationship on your storage system and map the secondary LUN to the secondary host again, or cancel mounting of the secondary LUN on the host and mount the secondary LUN again.
4. Run services on the secondary host in the DR center.

After the production center is recovered, perform the following operations to switch the services back to the production center if synchronous remote replication is configured:

1. Check whether the remote replication pair or consistency group is in the split state.
   1. If yes, go to the next step.
   2. If no, perform splitting and then go to the next step.

2. Perform a primary/secondary switchover.

   Before the switchover: the production center is the primary site and the DR center is the secondary site.

   After the switchover: the production center is the secondary site and the DR center is the primary site.

3. Enable secondary resource protection.

   During this operation, production hosts cannot be accessed. Before performing this operation, ensure that services on the production hosts can be suspended and suspend them.

4. Start synchronization.

   This operation synchronizes data from the DR center to the production center. Before performing this operation, ensure that data in the production center can be overwritten.

5. After data synchronization is complete, delete the mapping between the secondary host and the storage system.

   During this operation, hosts in the DR center cannot be accessed. Before performing this operation, ensure that host services in the DR center have been stopped.

6. Perform a primary/secondary switchover.

   Before the switchover: the production center is the secondary site and the DR center is the primary site.

   After the switchover: the production center is the primary site and the DR center is the secondary site.

7. Run services on the production host.

After the production center is recovered, perform the following operations to switch the services back to the production center if asynchronous remote replication is configured:

1. Check whether the remote replication pair or consistency group is in the split state.
   1. If yes, go to the next step.
   2. If no, perform splitting and then go to the next step.

2. Disable secondary resource protection.

3. Perform a primary/secondary switchover.

   Before the switchover: the production center is the primary site and the DR center is the secondary site.

   After the switchover: the production center is the secondary site and the DR center is the primary site.

4. Enable secondary resource protection.

   During this operation, production hosts cannot be accessed. Before performing this operation, ensure that services on the production hosts can be suspended and suspend them.

5. Start synchronization.

   This operation overwrites data in the production center using data in the DR center. Before performing this operation, ensure that data in the production center can be overwritten.

6. After data synchronization is complete, delete the mapping between the secondary host and the storage system.

   During this operation, hosts in the DR center cannot be accessed. Before performing this operation, ensure that host services in the DR center have been stopped.

7. Start synchronization to copy data from the DR storage system to the production storage system and ensure data consistency between the storage systems.

8. Perform the splitting.

9. Disable secondary resource protection.

10. After data replication is complete, perform a primary/secondary switchover on the production storage system.

    Before the switchover: the production center is the secondary site and the DR center is the primary site.

    After the switchover: the production center is the primary site and the DR center is the secondary site.

11. Enable secondary resource protection.

12. Start synchronization.

    Data is synchronized from the production center to the DR center. After synchronization, pair running status returns to normal.

13. Run services on the production host.