AWS Certified Solutions Architect – Associate (SAA-C02) — Question 315

A company wants to move its on-premises network attached storage (NAS) to AWS. The company wants to make the data available to any Linux instances within its VPC and ensure changes are automatically synchronized across all instances accessing the data store. The majority of the data is accessed very rarely, and some files are accessed by multiple users at the same time.
Which solution meets these requirements and is MOST cost-effective?

Answer options

• A. Create an Amazon Elastic Block Store (Amazon EBS) snapshot containing the data. Share it with users within the VPC.
• B. Create an Amazon S3 bucket that has a lifecycle policy set to transition the data to S3 Standard-Infrequent Access (S3 Standard-IA) after the appropriate number of days.
• C. Create an Amazon Elastic File System (Amazon EFS) file system within the VPC. Set the throughput mode to Provisioned and to the required amount of IOPS to support concurrent usage.
• D. Create an Amazon Elastic File System (Amazon EFS) file system within the VPC. Set the lifecycle policy to transition the data to EFS Infrequent Access (EFS IA) after the appropriate number of days.

Correct answer: D

Explanation

Amazon EFS is a shared file system that natively supports concurrent access from multiple Linux instances and automatically synchronizes changes. Since the majority of the data is accessed infrequently, using EFS with a lifecycle policy to transition data to EFS Infrequent Access (EFS IA) provides the most cost-effective solution. Amazon S3 and Amazon EBS do not natively support standard NAS/POSIX-compliant concurrent file-sharing needs for Linux instances as seamlessly as EFS, and Provisioned throughput would introduce unnecessary costs for rarely accessed data.