Answer: Migrate the PostgreSQL database to an Amazon RDS for PostgreSQL DB instance. Create a read replica in another Region.

## Explanation **Correct Answer: C** - Migrate the PostgreSQL database to an Amazon RDS for PostgreSQL DB instance. Create a read replica in another Region. **Why this is correct:** 1. **Multi-Region Availability**: The requirement states that data must be "available and online across multiple AWS Regions at all times." Creating a read replica in another Region provides a live, read-only copy of the database in a different Region. 2. **Least Operational Overhead**: Amazon RDS manages the replication process automatically. Once configured, RDS handles the ongoing replication, monitoring, and maintenance with minimal operational overhead. 3. **High Availability**: While the read replica is read-only, it can be promoted to a standalone database if needed, providing disaster recovery capabilities. **Analysis of other options:** **A. PostgreSQL cluster on Amazon EC2 instances:** - Requires significant operational overhead to set up and maintain cross-region replication manually - You would need to configure and manage PostgreSQL replication, monitoring, backups, and failover procedures - Not the solution with "LEAST amount of operational overhead" **B. RDS with Multi-AZ feature:** - Multi-AZ provides high availability within a single Region (across multiple Availability Zones) - Does NOT provide availability across multiple Regions - Only protects against AZ failures, not Region failures **D. RDS with DB snapshots copied to another Region:** - DB snapshots are backups, not live databases - Data is not "available and online" in the other Region - it would require restoration time - This is a disaster recovery solution, not continuous availability **Key AWS Concepts:** - **Cross-Region Read Replicas**: Provide asynchronous replication to another AWS Region - **Operational Overhead**: Managed services like RDS reduce operational burden compared to self-managed solutions - **Multi-Region Architecture**: For true multi-region availability, you need active or passive copies in different Regions **Best Practice**: For multi-region availability with minimal operational overhead, Amazon RDS cross-region read replicas are the recommended approach for PostgreSQL databases on AWS.

Author: LeetQuiz Editorial Team