AWS Certified Solutions Architect – Associate (SAA-C03) — Question 641

A solutions architect needs to copy files from an Amazon S3 bucket to an Amazon Elastic File System (Amazon EFS) file system and another S3 bucket. The files must be copied continuously. New files are added to the original S3 bucket consistently. The copied files should be overwritten only if the source file changes.

Which solution will meet these requirements with the LEAST operational overhead?

Answer options

• A. Create an AWS DataSync location for both the destination S3 bucket and the EFS file system. Create a task for the destination S3 bucket and the EFS file system. Set the transfer mode to transfer only data that has changed.
• B. Create an AWS Lambda function. Mount the file system to the function. Set up an S3 event notification to invoke the function when files are created and changed in Amazon S3. Configure the function to copy files to the file system and the destination S3 bucket.
• C. Create an AWS DataSync location for both the destination S3 bucket and the EFS file system. Create a task for the destination S3 bucket and the EFS file system. Set the transfer mode to transfer all data.
• D. Launch an Amazon EC2 instance in the same VPC as the file system. Mount the file system. Create a script to routinely synchronize all objects that changed in the origin S3 bucket to the destination S3 bucket and the mounted file system.

Correct answer: A

Explanation

AWS DataSync is a fully managed service that automates and accelerates data transfers between AWS storage services, making it the solution with the lowest operational overhead. Configuring the transfer mode to copy only changed data satisfies the requirement to overwrite files only when they are modified. Custom solutions involving AWS Lambda or Amazon EC2 require ongoing maintenance, while transferring all data in DataSync would be inefficient and violate the requirement to only copy changed files.