Which solution will allow this access in the MOST operationally efficient way?
Create an Amazon Elastic File System (Amazon EFS) Multi-AZ file system. Copy the files to the EFS file system. Connect the EFS file system to mount points on the application servers.
Create an Amazon FSx for Windows File Server Multi-AZ file system. Copy the files to the Amazon FSx file system. Adjust the connections from the application servers to use the share that the Amazon FSx file system exposes.
Create an Amazon Elastic Block Store (Amazon EBS) volume that has EBS Multi-Attach enabled. Create an Auto Scaling group for the Windows file server. Use a script in the file server’s user data to attach the SharedFileAccess tag to the EBS volume during launch.
Create two Amazon FSx for Windows File Server file systems. Configure Distributed File System (DFS) replication between the file systems. Copy the files to the Amazon FSx file systems. Adjust the connections from the application servers to use the shares that the Amazon FSx file systems expose.
Explanations:
Amazon EFS provides scalable, shared access for multiple EC2 instances across Availability Zones, but it is not a Windows-native solution. This would not be the most operationally efficient solution for Windows-based applications.
Amazon FSx for Windows File Server is a fully managed Windows file system that supports Multi-AZ deployments, providing native Windows file sharing across multiple EC2 instances. This allows simultaneous access to files in the most operationally efficient manner.
Amazon EBS Multi-Attach allows a volume to be attached to multiple instances, but it does not provide file-level access across instances. EBS is not designed for shared file storage across multiple EC2 instances, and this solution is not suitable for Windows file server scenarios.
Configuring two FSx file systems with DFS replication is unnecessarily complex and introduces overhead, as DFS replication is typically used for distributing file data across geographically separated sites, not for enabling simple shared access between application servers.
I draft that the answer is:
Create an Amazon FSx for Windows File Server Multi-AZ file system. Copy the files to the Amazon FSx file system. Adjust the connections from the application servers to use the share that the Amazon FSx file system exposes.