Which solution will meet these business requirements at the LOWEST cost?
Deploy an Amazon Aurora DB cluster and take snapshots of the cluster every 5 minutes. Once a snapshot is complete, copy the snapshot to a secondary Region to serve as a backup in the event of a failure.
Deploy an Amazon RDS instance with a cross-Region read replica in a secondary Region. In the event of a failure, promote the read replica to become the primary.
Deploy an Amazon Aurora DB cluster in the primary Region and another in a secondary Region. Use AWS DMS to keep the secondary Region in sync.
Deploy an Amazon RDS instance with a read replica in the same Region. In the event of a failure, promote the read replica to become the primary.
Explanations:
While taking snapshots every 5 minutes can provide backups, snapshots are not immediate failover solutions and can take longer than 10 minutes to restore, thus not meeting the RTO requirement.
An Amazon RDS instance with a cross-Region read replica allows for fast promotion of the read replica to primary in the event of failure. This solution can meet both the RPO (less than 5 minutes) and RTO (less than 10 minutes) requirements efficiently.
While having two Aurora clusters in different Regions with AWS DMS for synchronization can work, it is likely to be more expensive due to the need for maintaining two active clusters and the DMS service. Additionally, synchronization latency could complicate meeting the RPO requirement.
Deploying an RDS instance with a read replica in the same Region will not meet the requirement for cross-Region failover. In the event of a failure, the primary and the read replica are still in the same Region, which does not provide a true disaster recovery solution.