The most cost-effective solution for high CPU on a read-heavy RDS MySQL instance is to create one or more read replicas and direct read traffic to them. This works because read replicas offload SELECT queries from the primary database, reducing its CPU utilization without requiring expensive vertical scaling. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of horizontal scaling for read-heavy workloads versus the common trap of choosing a larger instance size, which is more costly and less efficient. A key memory tip is to think “read replicas for read relief” — when you see high CPU from SELECT queries, replicas are the budget-friendly fix, not bigger hardware or more storage.
DBS-C01 Management and Operations Practice Question
This DBS-C01 practice question tests your understanding of management and operations. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A database administrator notices that Amazon RDS for MySQL is experiencing high CPU utilization during peak hours. The application is read-heavy with many SELECT queries. Which action is most cost-effective to improve performance?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create one or more read replicas and direct read traffic to them.
Option C is correct because read replicas offload read traffic from the primary, reducing CPU utilization. Option A is wrong because increasing instance size is more expensive and may not be optimal. Option B is wrong because vertical scaling is not the most cost-effective. Option D is wrong because adding storage does not reduce CPU.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Create one or more read replicas and direct read traffic to them.
Read the scenario before looking for a memorised answer.
✗
Increase the DB instance class to a larger size.
Why it's wrong here
Larger instance is more expensive and may not be necessary.
✗
Increase the allocated storage to improve I/O throughput.
Why it's wrong here
Storage increase does not reduce CPU utilization.
✗
Scale up the DB instance vertically to a higher vCPU count.
Why it's wrong here
Vertical scaling is costlier than adding read replicas.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which DBS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Management and Operations — This question tests Management and Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create one or more read replicas and direct read traffic to them. — Option C is correct because read replicas offload read traffic from the primary, reducing CPU utilization. Option A is wrong because increasing instance size is more expensive and may not be optimal. Option B is wrong because vertical scaling is not the most cost-effective. Option D is wrong because adding storage does not reduce CPU.
What should I do if I get this DBS-C01 question wrong?
Identify which DBS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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