Which solution will meet these requirements with the LEAST amount of operational overhead?
Migrate the PostgreSQL database to a PostgreSQL cluster on Amazon EC2 instances.
Migrate the PostgreSQL database to an Amazon RDS for PostgreSQL DB instance with the Multi-AZ feature turned on.
Migrate the PostgreSQL database to an Amazon RDS for PostgreSQL DB instance. Create a read replica in another Region.
Migrate the PostgreSQL database to an Amazon RDS for PostgreSQL DB instance. Set up DB snapshots to be copied to another Region.
Explanations:
Migrating the PostgreSQL database to a PostgreSQL cluster on Amazon EC2 instances involves significant operational overhead, including managing the cluster, backups, and failovers. This solution does not inherently provide high availability or cross-region replication.
While using Amazon RDS for PostgreSQL with Multi-AZ provides high availability within a single Region, it does not address the requirement for data availability across multiple AWS Regions. Multi-AZ only enhances availability and durability within the same Region.
Migrating to Amazon RDS for PostgreSQL and creating a read replica in another Region ensures that the data is available online across multiple Regions. This solution minimizes operational overhead as Amazon RDS manages the database instance, and read replicas can handle read traffic without manual management.
Although creating DB snapshots to be copied to another Region allows for backup and recovery, it does not provide real-time availability of data across Regions. Snapshots are not live and can only be restored, thus failing to meet the requirement for online access at all times.
I estimate that the answer is:
Migrate the PostgreSQL database to an Amazon RDS for PostgreSQL DB instance. Create a read replica in another Region.