SAP-C02 AWS Database Migration Service (DMS) Practice Question
A company is migrating a legacy on-premises application to AWS. The application consists of a web server, an application server, and a MySQL database. The company has already migrated the web and application servers to EC2 instances in a VPC. The database is still on-premises. The application currently connects to the database using a JDBC connection string with the on-premises IP address. The company wants to minimize changes to the application code. The network team has established an AWS Direct Connect connection between the on-premises data center and the VPC. The security team requires that traffic between the application and the database be encrypted in transit. The database is not publicly accessible. The migration plan includes moving the database to Amazon RDS for MySQL in the same VPC after the initial cutover. During the migration testing phase, the application team reports that the application can connect to the on-premises database but performance is slower than expected. CloudWatch metrics show high latency on the database connections. The application uses a connection pool with 100 connections. Which solution should the solutions architect recommend to improve performance while minimizing application code changes?
⚠ Common exam trap
Candidates may incorrectly choose option B (read replica) thinking it can replicate from on-premises, but RDS read replicas only work with an RDS source. The correct approach is to use DMS to replicate the on-premises database to an RDS instance in the cloud.
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
✓
Use AWS Database Migration Service to set up ongoing replication from on-premises to RDS
AWS Database Migration Service (DMS) with ongoing replication can continuously replicate data from the on-premises MySQL database to an Amazon RDS for MySQL instance in the same VPC. This allows the application to connect to the local RDS instance, significantly reducing latency compared to the Direct Connect link. To minimize code changes, the application's JDBC connection string can be updated to point to the RDS endpoint, or a DNS CNAME can be used to abstract the change. Option A (increasing connection pool size) does not reduce network latency and may worsen performance. Option B (read replica) is not feasible because an RDS read replica can only replicate from an RDS primary, not from an on-premises database. Option D (Multi-AZ) is not applicable until the database is on AWS and does not improve latency.
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 connection pool size to 200 and enable connection multiplexing
Why it's wrong here
Increasing connection pool size to 200 and enabling connection multiplexing may reduce connection overhead but does not address the high network latency caused by the Direct Connect link to the on-premises database. It could even increase contention and not improve performance.
- ✗
Deploy an Amazon RDS for MySQL read replica in the same Region and direct read traffic to it
Why it's wrong here
A read replica requires an existing RDS primary instance. Since the database is still on-premises, an RDS read replica cannot be created to replicate from on-premises. This option is not feasible during the testing phase.
- ✓
Use AWS Database Migration Service to set up ongoing replication from on-premises to RDS
Why this is correct
Using DMS with ongoing replication creates an RDS instance in the VPC that stays synchronized with the on-premises database. The application can then be pointed to this local RDS instance, drastically reducing latency. This is the most effective solution with minimal application changes.
- ✗
Enable Multi-AZ on the RDS instance
Why it's wrong here
Multi-AZ provides high availability for an RDS instance but does not reduce read latency. Additionally, no RDS instance exists yet, so this option is not applicable.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAP-C02 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 SAP-C02 exam.