AWS Certified Solutions Architect – Professional — Question 833

A company has an existing on-premises three-tier web application. The Linux web servers serve content from a centralized file share on a NAS server because the content is refreshed several times a day from various sources. The existing infrastructure is not optimized and the company would like to move to AWS in order to gain the ability to scale resources up and down in response to load. On-premises and AWS resources are connected using AWS Direct Connect.
How can the company migrate the web infrastructure to AWS without delaying the content refresh process?

Answer options

• A. Create a cluster of web server Amazon EC2 instances behind a Classic Load Balancer on AWS. Share an Amazon EBS volume among all instances for the content. Schedule a periodic synchronization of this volume and the NAS server.
• B. Create an on-premises file gateway using AWS Storage Gateway to replace the NAS server and replicate content to AWS. On the AWS side, mount the same Storage Gateway bucket to each web server Amazon EC2 instance to serve the content.
• C. Expose an Amazon EFS share to on-premises users to serve as the NAS serve. Mount the same EFS share to the web server Amazon EC2 instances to serve the content.
• D. Create web server Amazon EC2 instances on AWS in an Auto Scaling group. Configure a nightly process where the web server instances are updated from the NAS server.

Correct answer: C

Explanation

Amazon EFS is a managed NFS file system that can be concurrently mounted on-premises via AWS Direct Connect and on Amazon EC2 instances, ensuring immediate access to content updates without sync delays. Option A is incorrect because standard Amazon EBS volumes cannot be shared across multiple instances in this manner, and periodic syncs introduce delays. Options B and D are incorrect because nightly updates or Storage Gateway caching mechanisms would fail to support the requirement of immediate, multi-times-a-day content refreshes.