Azure DMS - point applications at target DB before cutover

Question

When running an online migration with Azure Database Migration Service, are there any issues with pointing applications at the target database before running the cutover in DMS? In the cutover action in DMS it says to stop writes on the source DB to make sure that any pending updates are applied to the target DB, but wouldn't any pending updates still be replicated to the target DB without needing to stop writes on the source? Is there something that DMS does during the cutover that would prevent applications from using the target DB?

Answer 1

@Reed In online migration, during the cutover target db goes through the recovery process and is unavailable for any reads and writes. But once the cutover is completed successfully, target db can start taking the reads and writes both.

In case of VM and MI, DMS uses backup and restore. We ask to stop the application just before the cutover to get data consistency between source and target by taking final log backup when there is no writes happening on source and then restoring it to Target.

Let me know if you are looking for any additional information.

Regards

Geetha