AWS Certified Solutions Architect – Associate (SAA-C03) — Question 524

A company runs a three-tier web application in the AWS Cloud that operates across three Availability Zones. The application architecture has an Application Load Balancer, an Amazon EC2 web server that hosts user session states, and a MySQL database that runs on an EC2 instance. The company expects sudden increases in application traffic. The company wants to be able to scale to meet future application capacity demands and to ensure high availability across all three Availability Zones.

Which solution will meet these requirements?

Answer options

• A. Migrate the MySQL database to Amazon RDS for MySQL with a Multi-AZ DB cluster deployment. Use Amazon ElastiCache for Redis with high availability to store session data and to cache reads. Migrate the web server to an Auto Scaling group that is in three Availability Zones.
• B. Migrate the MySQL database to Amazon RDS for MySQL with a Multi-AZ DB cluster deployment. Use Amazon ElastiCache for Memcached with high availability to store session data and to cache reads. Migrate the web server to an Auto Scaling group that is in three Availability Zones.
• C. Migrate the MySQL database to Amazon DynamoDB Use DynamoDB Accelerator (DAX) to cache reads. Store the session data in DynamoDB. Migrate the web server to an Auto Scaling group that is in three Availability Zones.
• D. Migrate the MySQL database to Amazon RDS for MySQL in a single Availability Zone. Use Amazon ElastiCache for Redis with high availability to store session data and to cache reads. Migrate the web server to an Auto Scaling group that is in three Availability Zones.

Correct answer: A

Explanation

Option A is correct because utilizing Amazon RDS for MySQL with a Multi-AZ DB cluster deployment ensures database high availability, while Amazon ElastiCache for Redis provides a highly available, replicated data store ideal for session states. Option B is incorrect because Memcached lacks the native multi-AZ replication and failover capabilities needed for highly available session storage. Option D fails to meet the high availability requirement by deploying the database in a single Availability Zone, and Option C involves a complex, unnecessary database paradigm shift from relational MySQL to NoSQL DynamoDB.