AWS Certified Solutions Architect – Associate (SAA-C03) — Question 376

A company runs an application on Amazon EC2 Linux instances across multiple Availability Zones. The application needs a storage layer that is highly available and Portable Operating System Interface (POSIX)-compliant. The storage layer must provide maximum data durability and must be shareable across the EC2 instances. The data in the storage layer will be accessed frequently for the first 30 days and will be accessed infrequently after that time.

Which solution will meet these requirements MOST cost-effectively?

Answer options

• A. Use the Amazon S3 Standard storage class. Create an S3 Lifecycle policy to move infrequently accessed data to S3 Glacier.
• B. Use the Amazon S3 Standard storage class. Create an S3 Lifecycle policy to move infrequently accessed data to S3 Standard-Infrequent Access (S3 Standard-IA).
• C. Use the Amazon Elastic File System (Amazon EFS) Standard storage class. Create a lifecycle management policy to move infrequently accessed data to EFS Standard-Infrequent Access (EFS Standard-IA).
• D. Use the Amazon Elastic File System (Amazon EFS) One Zone storage class. Create a lifecycle management policy to move infrequently accessed data to EFS One Zone-Infrequent Access (EFS One Zone-IA).

Correct answer: C

Explanation

Amazon EFS is required because Amazon S3 is object storage and does not natively support POSIX-compliant file system sharing for EC2 instances, ruling out options A and B. To achieve high availability and maximum durability across multiple Availability Zones, EFS Standard must be used instead of EFS One Zone, which is restricted to a single zone. Implementing an EFS lifecycle policy to transition data to EFS Standard-IA after 30 days optimizes costs while fully meeting all technical requirements.