AWS Certified SysOps Administrator – Associate (legacy) — Question 129

You run a web application with the following components Elastic Load Balancer (EL8), 3 Web/Application servers, 1 MySQL RDS database with read replicas, and
Amazon Simple Storage Service (Amazon S3) for static content. Average response time for users is increasing slowly.
What three CloudWatch RDS metrics will allow you to identify if the database is the bottleneck? (Choose three.)

Answer options

• A. The number of outstanding IOs waiting to access the disk.
• B. The amount of write latency.
• C. The amount of disk space occupied by binary logs on the master.
• D. The amount of time a Read Replica DB Instance lags behind the source DB Instance
• E. The average number of disk I/O operations per second.

Correct answer: A, B, D

Explanation

The correct answers, A, B, and D, directly indicate the performance and latency issues related to the database. Option A measures the pending IO requests, which can show disk access bottlenecks, while B reflects how long write operations are taking. D indicates how behind a Read Replica is, which can affect overall read performance. Options C and E, while informative, do not directly relate to identifying database bottlenecks in the context of response time.