AWS Certified Developer – Associate (DVA-C02) — Question 154

An application runs on multiple EC2 instances behind an ELB.

Where is the session data best written so that it can be served reliably across multiple requests?

Answer options

• A. Write data to Amazon ElastiCache.
• B. Write data to Amazon Elastic Block Store.
• C. Write data to Amazon EC2 Instance Store.
• D. Write data to the root filesystem.

Correct answer: A

Explanation

The correct answer is A, as Amazon ElastiCache provides a distributed caching solution that allows session data to be shared across multiple EC2 instances, ensuring high availability and quick access. The other options, such as Amazon Elastic Block Store and EC2 Instance Store, are not designed for this purpose, as they are tied to individual instances and can lead to session data loss or inconsistency. Writing to the root filesystem is also not reliable in a load-balanced environment, as different instances may not share the same filesystem.