AWS Certified Developer – Associate (DVA-C02) — Question 510

A developer is building a three-tier web application that should be able to handle a minimum of 5000 requests per minute. Requirements state that the web tier should be completely stateless while the application maintains session state for the users.

How can session data be externalized, keeping latency at the LOWEST possible value?

Answer options

• A. Create an Amazon RDS instance, then implement session handling at the application level to leverage a database inside the RDS database instance for session data storage.
• B. Implement a shared file system solution across the underlying Amazon EC2 instances, then implement session handling at the application level to leverage the shared file system for session data storage.
• C. Create an Amazon ElastiCache (Memcached) cluster, then implement session handling at the application level to leverage the cluster for session data storage.
• D. Create an Amazon DynamoDB table, then implement session handling at the application level to leverage the table for session data storage.

Correct answer: C

Explanation

Amazon ElastiCache (Memcached) is an in-memory key-value store designed to deliver sub-millisecond response times, making it the lowest latency option for session state storage. Although Amazon DynamoDB is highly scalable and offers single-digit millisecond latency, it is still slower than an in-memory cache like ElastiCache. Amazon RDS and shared file systems rely on disk-based storage, which introduces significantly higher latency and is not suitable for ultra-low latency requirements.