DEA-C01 Data Store Management Practice Question
A company is running a production Amazon RDS for MySQL Multi-AZ DB instance. The database experiences a sudden spike in read requests, causing performance degradation. The company needs to improve read scalability with minimal application changes. Which solution should the data engineer recommend?
⚠ Common exam trap
Test-takers frequently confuse Multi-AZ with read scaling, assuming the standby replica can serve reads, but AWS explicitly disables reads on the Multi-AZ standby to maintain data consistency and failover integrity.
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 an Amazon RDS Read Replica and update the application to use it for read queries.
Amazon RDS Read Replicas allow you to offload read traffic from the primary DB instance by creating asynchronous replicas that can serve read queries. This directly addresses the spike in read requests with minimal application changes—only the connection string for read queries needs to be updated. Multi-AZ is for high availability, not read scaling, and increasing instance size is a vertical scaling approach that doesn't leverage the horizontal read scalability of replicas.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Implement DynamoDB Accelerator (DAX) in front of the database.
Why it's wrong here
DAX is for DynamoDB, not RDS.
- ✗
Enable Multi-AZ on the existing DB instance.
Why it's wrong here
Multi-AZ provides high availability, not read scaling.
- ✗
Increase the DB instance size to a larger instance class.
Why it's wrong here
Vertical scaling can help but does not scale reads horizontally and may be more expensive.
- ✓
Create an Amazon RDS Read Replica and update the application to use it for read queries.
Why this is correct
Read Replicas handle read traffic, offloading the primary instance and improving scalability.
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Same concept, more angles
3 more ways this is tested on DEA-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is using Amazon RDS for MySQL with Multi-AZ deployment. The database experiences intermittent slowdowns during peak hours. The company's DevOps team suspects that the primary instance is overwhelmed. Which action should the team take to distribute the read load without changing the application code?
medium- A.Increase the instance size of the RDS instance.
- ✓ B.Create a read replica and modify the connection string to point to the replica for read queries.
- C.Enable Multi-AZ on the existing instance.
- D.Configure DynamoDB Accelerator (DAX) in front of the RDS instance.
Why B: Creating a read replica and modifying the connection string to point to the replica for read queries (Option B) offloads read traffic from the primary RDS instance without requiring application code changes. This directly addresses the intermittent slowdowns during peak hours by distributing the read load, leveraging MySQL’s native replication to keep the replica synchronized. The key constraint is 'without changing the application code,' which is satisfied by simply updating the connection string in the application configuration.
Variation 2. 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?
medium- A.Use Amazon ElastiCache to cache database queries
- B.Increase the instance size to 16xlarge
- ✓ C.Create Read Replicas in the same or different regions
- D.Enable Multi-AZ on additional instances
Why C: 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.
Variation 3. A company has an Amazon RDS for MySQL database that is experiencing performance issues due to a large number of read requests. The application is read-heavy and can tolerate eventually consistent reads. Which action will reduce the load on the primary database with the least operational overhead?
hard- ✓ A.Create a read replica in the same region
- B.Use Amazon ElastiCache for caching
- C.Enable Multi-AZ deployment
- D.Increase the instance size of the primary DB
Why A: Creating a read replica in the same region offloads read traffic from the primary RDS instance to a read-only copy, which directly addresses the read-heavy workload. Since the application can tolerate eventually consistent reads, the slight replication lag is acceptable, and this solution requires minimal operational overhead—just a few clicks in the AWS console or a single API call—without any application code changes.
JA
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.