The correct answer is Migrate the PostgreSQL database to an Amazon RDS for PostgreSQL DB instance. Create a read replica in another Region.

This solution provides asynchronous cross-Region replication using Amazon RDS, which ensures that customer data is continually duplicated to another AWS Region. In the event of a failure in the primary Region, the read replica can be promoted to a standalone database instance. This setup minimizes management burden while satisfying the requirement for multi-Region availability and disaster recovery.

Migrate the PostgreSQL database to a PostgreSQL cluster on Amazon EC2 instances offers control but adds significant operational complexity. You are responsible for managing updates, replication, failover, and network security across Regions.

Migrate the PostgreSQL database to an Amazon RDS for PostgreSQL DB instance with the Multi-AZ feature turned on improves fault tolerance within a single Region but does not provide cross-Region resilience, which disqualifies it from meeting the scenarios requirements.

Migrate the PostgreSQL database to an Amazon RDS for PostgreSQL DB instance. Set up DB snapshots to be copied to another Region enables backup-based disaster recovery but does not ensure continuous availability. Snapshots are point-in-time and require manual recovery, which introduces downtime.

Why this question is important: It evaluates your knowledge of designing for fault tolerance and high availability across Regions. Knowing when to use read replicas, Multi-AZ, and backups is key for architecting resilient systems on AWS.

Tip: If the question emphasizes automatic availability in multiple Regions with minimal effort, cross-Region read replicas on Amazon RDS are often the best-fit answer.

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