What is the MOST operationally efficient solution that meets these requirements?
Modify the DB instance. Enable cross-Region automated backups.
Create an RDS read replica in another Region. Create a snapshot of the read replica.
Use AWS Database Migration Service (AWS DMS) to copy the data to a DB instance in another Region.
Temporarily turn off encryption on the DB instance. Take a snapshot. Copy the snapshot to another Region.
Explanations:
Enabling cross-Region automated backups for an encrypted RDS instance is the most operationally efficient way to ensure backups are available in another Region. This feature automatically replicates the backups to the target Region without needing manual intervention, while maintaining encryption.
Creating an RDS read replica in another Region is a good approach for read scalability, but it is not specifically designed for backups. Snapshots of read replicas are not an efficient or direct way to manage cross-Region backups.
AWS DMS is used for database migrations and replication, but it is not designed for backup purposes. Using DMS to copy data would be an unnecessary and complex approach for this use case.
Temporarily turning off encryption to take a snapshot and then copying it to another Region would expose data to risk during the time encryption is disabled. Additionally, it’s a manual and inefficient process compared to using cross-Region automated backups.
If I had to guess, I’d say the answer is:
Modify the DB instance. Enable cross-Region automated backups.