DBS-C01 Monitoring and Troubleshooting Practice Question
A company is experiencing high read latency on their Amazon RDS for MySQL Multi-AZ DB instance. The application performs many small, random reads. Which configuration change would most likely reduce the read latency without incurring additional compute costs?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable Multi-AZ DB cluster deployment with two readable standby instances and route read traffic to the standby.
The Multi-AZ DB cluster deployment for Amazon RDS includes two readable standby instances. By routing read traffic to these standbys, the load on the primary is reduced, which can decrease read latency without additional compute costs since the standbys are already provisioned. Option A is incorrect because increasing allocated storage primarily improves I/O throughput for sequential operations but may not significantly reduce latency for many small random reads. Option B is incorrect because Performance Insights is a monitoring tool that helps identify performance bottlenecks but does not directly reduce read latency. Option D is incorrect because increasing the instance size (e.g., from db.r5.large to db.r5.xlarge) would incur additional compute costs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the allocated storage size to improve I/O throughput.
Why it's wrong here
Allocated storage size does not directly affect read latency for random reads.
- ✗
Enable Performance Insights to monitor and optimize queries.
Why it's wrong here
Performance Insights helps identify performance bottlenecks but does not directly reduce read latency.
- ✓
Enable Multi-AZ DB cluster deployment with two readable standby instances and route read traffic to the standby.
Why this is correct
This offloads read traffic to the standby, reducing load on the primary and improving read latency.
- ✗
Increase the instance size from db.r5.large to db.r5.xlarge.
Why it's wrong here
This would increase compute costs, not reducing costs.
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Variation 1. A company is running an Amazon RDS for MySQL Multi-AZ DB instance. They notice that the application is experiencing increased latency during peak hours. The DB instance's CPU utilization is consistently above 80%, and the Read Latency metric is high. Which action would most effectively reduce the latency without requiring application changes?
medium- ✓ A.Create a read replica and direct read queries to it.
- B.Disable Multi-AZ to free up resources.
- C.Increase the DB instance class to a larger size.
- D.Enable Multi-AZ on the DB instance.
Why A: Creating a read replica offloads read queries from the primary DB instance, reducing read latency and CPU utilization without requiring application changes. Option B is incorrect because disabling Multi-AZ removes the standby instance, reducing availability and not addressing read latency. Option C is incorrect because increasing the instance class may improve performance but does not specifically offload read traffic; read replicas are more targeted for read-heavy workloads. Option D is incorrect because the instance already has Multi-AZ enabled; enabling it again has no effect and does not reduce read latency.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DBS-C01 exam.