AWS Certified Solutions Architect – Associate (SAA-C02) — Question 635

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 Amazon RDS instance from Single-AZ to Multi-AZ is a seamless process that AWS handles automatically by creating a standby replica in a different Availability Zone and synchronizing the data, requiring no application code changes and minimizing downtime. Option B introduces unnecessary downtime and configuration overhead by requiring a manual snapshot and restore process. Options C and D are incorrect because read replicas and EC2 Auto Scaling do not provide automatic, transparent failover for write operations without application code modifications.