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 to a PostgreSQL cluster on Amazon EC2 instances requires significant operational overhead for managing the EC2 instances, including backups, patching, scaling, and availability configurations. This does not ensure high availability across multiple Regions without manual setup.
Using Amazon RDS for PostgreSQL with Multi-AZ provides high availability and failover support within a single AWS Region but does not replicate data across multiple Regions, thus failing the requirement for global availability.
Migrating the PostgreSQL database to Amazon RDS for PostgreSQL and creating a read replica in another Region meets the requirement for data availability across multiple AWS Regions. RDS handles backups, scaling, and maintenance with minimal operational overhead, and the read replica ensures that data is online and available in another Region.
While RDS snapshots can be copied to another Region for backup purposes, this does not provide real-time data availability. Snapshots are not continuously updated, meaning that the data may be stale and not immediately available, which does not meet the requirement for constant availability across Regions.
I plot that the answer is:
Migrate the PostgreSQL database to an Amazon RDS for PostgreSQL DB instance. Create a read replica in another Region.