AWS Certified Solutions Architect – Associate (SAA-C03) — Question 450

A company hosts an online shopping application that stores all orders in an Amazon RDS for PostgreSQL Single-AZ DB instance. Management wants to eliminate single points of failure and has asked a solutions architect to recommend an approach to minimize database downtime without requiring any changes to the application code.

Which solution meets these requirements?

Answer options

• A. Convert the existing database instance to a Multi-AZ deployment by modifying the database instance and specifying the Multi-AZ option.
• B. Create a new RDS Multi-AZ deployment. Take a snapshot of the current RDS instance and restore the new Multi-AZ deployment with the snapshot.
• C. Create a read-only replica of the PostgreSQL database in another Availability Zone. Use Amazon Route 53 weighted record sets to distribute requests across the databases.
• D. Place the RDS for PostgreSQL database in an Amazon EC2 Auto Scaling group with a minimum group size of two. Use Amazon Route 53 weighted record sets to distribute requests across instances.

Correct answer: A

Explanation

Modifying an existing Amazon RDS instance to a Multi-AZ deployment is a seamless administrative action that automatically provisions a standby replica in a different Availability Zone without altering the DB instance endpoint, resulting in zero application code changes. Option B introduces unnecessary downtime and complexity due to manual snapshotting and restoration. Options C and D are incorrect because read replicas and EC2 Auto Scaling groups do not provide automatic failover for write traffic without application-side code changes to manage write/read routing.