DEA-C01 Data Store Management Practice Question
A company is using Amazon RDS for MySQL with Multi-AZ deployment. The database size is 2 TB and the workload is read-heavy. To improve read performance, which option should be used?
⚠ Common exam trap
Many candidates confuse Multi-AZ with read scaling, assuming the standby instance can serve reads, but Multi-AZ is strictly for high availability and disaster recovery, not for read traffic.
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 Read Replicas in the same or different regions
Amazon RDS for MySQL Read Replicas offload read traffic from the primary DB instance, directly improving read performance for a read-heavy workload. With a 2 TB database, Read Replicas can be created in the same or different regions, providing horizontal read scaling without impacting the primary instance's write capacity. Multi-AZ deployment already provides high availability but does not improve read performance, as the standby instance is not used for 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.
- ✗
Use Amazon ElastiCache to cache database queries
Why it's wrong here
ElastiCache caches query results in memory but leaves the underlying read-heavy load on the primary; Multi-AZ standby replicas serve no reads. It is tempting because caching offloads repeated identical queries, and would be correct for a workload dominated by repeated, cacheable read patterns rather than general read scaling.
- ✗
Increase the instance size to 16xlarge
Why it's wrong here
Scaling the instance vertically adds CPU and memory, but Multi-AZ standby nodes serve no read traffic, so a single larger primary still absorbs every query. It tempts because burstable compute helps CPU-bound workloads; read replicas, not instance size, offload read-heavy 2 TB MySQL databases.
- ✓
Create Read Replicas in the same or different regions
Why this is correct
Read Replicas asynchronously copy the primary via MySQL's binlog, and applications can direct read-only queries to them, offloading the read-heavy workload from the primary. Multi-AZ standby exists solely for failover and cannot serve reads, so it adds no read throughput.
- ✗
Enable Multi-AZ on additional instances
Why it's wrong here
Multi-AZ is a high-availability failover configuration, not a read-scaling mechanism; each standby replicates synchronously and serves no queries. It tempts as an availability safeguard, but the requirement is read throughput, which read replicas address by serving traffic independently.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-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 DEA-C01 exam.