DBS-C01 Workload-Specific Database Design Practice Question

Network Topology

Refer to the exhibit. An application team notices that the MySQL RDS instance 'mydb' is running at 80% CPU utilization during peak hours. They need to improve read performance without increasing the CPU load on the primary instance. Which action should they take?

⚠ Common exam trap

Candidates often confuse Multi-AZ (which provides failover but no read scaling) with Read Replicas (which offload reads), leading candidates to select Multi-AZ when the goal is to reduce CPU load on the primary.

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

✓

Create a Read Replica in the same region

Creating a Read Replica offloads read traffic from the primary MySQL RDS instance, reducing CPU load on the primary while improving read performance for applications. Read Replicas asynchronously replicate data using MySQL’s native binlog-based replication, allowing the primary to focus on write operations without additional CPU overhead from serving reads.

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 DB instance class to db.r5.xlarge
Why it's wrong here
Scales vertically but does not offload reads; still single point of load.
✓
Create a Read Replica in the same region
Why this is correct
Read Replica offloads read queries, reducing CPU on primary.
✗
Change storage type to io1 with higher IOPS
Why it's wrong here
Storage change does not reduce CPU utilization.
✗
Enable Multi-AZ deployment
Why it's wrong here
Multi-AZ provides high availability, not read scaling.

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DBS-C01 Workload-Specific Database Design Practice Question

Why each option matters

Option-by-option breakdown

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