AWS Certified Solutions Architect – Associate (SAA-C03) — Question 920

A company uses an Amazon RDS for MySQL instance. To prepare for end-of-year processing, the company added a read replica to accommodate extra read-only queries from the company's reporting tool. The read replica CPU usage was 60% and the primary instance CPU usage was 60%.

After end-of-year activities are complete, the read replica has a constant 25% CPU usage. The primary instance still has a constant 60% CPU usage. The company wants to rightsize the database and still provide enough performance for future growth.

Which solution will meet these requirements?

Answer options

• A. Delete the read replica Do not make changes to the primary instance
• B. Resize the read replica to a smaller instance size Do not make changes to the primary instance
• C. Resize the read replica to a larger instance size Resize the primary instance to a smaller instance size
• D. Delete the read replica Resize the primary instance to a larger instance

Correct answer: B

Explanation

The primary instance's CPU utilization is steady at 60%, which represents an optimal balance of performance and headroom for future growth, so its size should remain unchanged. The read replica's CPU utilization has decreased to 25%, indicating it is over-provisioned for the current workload and can be safely downsized to optimize costs. Deleting the read replica is not an option because it is still needed to handle the reporting tool's queries.