AWS Certified Solutions Architect – Associate (SAA-C02) — Question 544

A solutions architect is migrating a document management workload to AWS. The workload keeps 7 TiB of contract documents on a shared storage file system and tracks them on an external database. Most of the documents are stored and retrieved eventually for reference in the future. The application cannot be modified during the migration, and the storage solution must be highly available.
Documents are retrieved and stored by web servers that run on Amazon EC2 instances in an Auto Scaling group. The Auto Scaling group can have up to 12 instances.
Which solution meets these requirements MOST cost-effectively?

Answer options

• A. Provision an enhanced networking optimized EC2 instance to serve as a shared NFS storage system.
• B. Create an Amazon S3 bucket that uses the S3 Standard-Infrequent Access (S3 Standard-IA) storage class. Mount the S3 bucket to the EC2 instances in the Auto Scaling group.
• C. Create an SFTP server endpoint by using AWS Transfer for SFTP and an Amazon S3 bucket. Configure the EC2 instances in the Auto Scaling group to connect to the SFTP server.
• D. Create an Amazon Elastic File System (Amazon EFS) file system that uses the EFS Standard-Infrequent Access (EFS Standard-IA) storage class. Mount the file system to the EC2 instances in the Auto Scaling group.

Correct answer: D

Explanation

Amazon EFS provides a highly available, fully managed shared file system that can be mounted natively on multiple EC2 instances without requiring any changes to the application code. Utilizing the EFS Standard-Infrequent Access (EFS Standard-IA) storage class ensures the solution is highly cost-effective for infrequently accessed documents. Other options like Amazon S3 are object-based and would require application modifications, while a single EC2-based NFS server lacks high availability.