AWS Certified Developer – Associate (DVA-C02) — Question 43

A developer needs to migrate an online retail application to AWS to handle an anticipated increase in traffic. The application currently runs on two servers: one server for the web application and another server for the database. The web server renders webpages and manages session state in memory. The database server hosts a MySQL database that contains order details. When traffic to the application is heavy, the memory usage for the web server approaches 100% and the application slows down considerably.
The developer has found that most of the memory increase and performance decrease is related to the load of managing additional user sessions. For the web server migration, the developer will use Amazon EC2 instances with an Auto Scaling group behind an Application Load Balancer.
Which additional set of changes should the developer make to the application to improve the application's performance?

Answer options

• A. Use an EC2 instance to host the MySQL database. Store the session data and the application data in the MySQL database.
• B. Use Amazon ElastiCache for Memcached to store and manage the session data. Use an Amazon RDS for MySQL DB instance to store the application data.
• C. Use Amazon ElastiCache for Memcached to store and manage the session data and the application data.
• D. Use the EC2 instance store to manage the session data. Use an Amazon RDS for MySQL DB instance to store the application data.

Correct answer: B

Explanation

The correct answer is B because using Amazon ElastiCache for Memcached allows for efficient management of session data, reducing the memory load on the web servers, while Amazon RDS for MySQL ensures reliable storage for application data. Option A is incorrect as storing session data in MySQL can lead to performance issues similar to those currently faced. Option C is not ideal since managing application data in ElastiCache is not suitable for persistent data needs. Option D is also not recommended because the EC2 instance store is ephemeral and could result in data loss.