A company's solutions architect is reviewing a web application that runs on AWS. The application references static assets in an Amazon S3 bucket in the us-east-1 Region. The company needs resiliency across multiple AWS Regions. The company already has created an S3 bucket in a second Region. Which solution will meet these requirements with the LEAST operational overhead?

This solution provides the highest resiliency with the lowest operational overhead by leveraging two fully managed AWS services. S3 Cross-Region Replication (CRR) automatically and asynchronously copies objects from the primary bucket to the secondary bucket without requiring any custom code or application logic. Amazon CloudFront with an origin group provides automated failover at the content delivery layer. If the primary origin (the us-east-1 S3 bucket) becomes unavailable, CloudFront will automatically route user requests to the secondary origin (the S3 bucket in the second region). This combination creates a robust, self-healing architecture that requires only initial configuration, perfectly aligning with the "least operational overhead" requirement.

A. Requiring the application to perform dual writes adds significant complexity and a point of failure to the application code, which increases, rather than minimizes, operational overhead.
B. Using a custom AWS Lambda function to replicate objects requires development, deployment, and ongoing maintenance, which has higher operational overhead than the managed S3 Replication service.
D. A manual failover process that requires updating application code is slow, error-prone, and involves significant operational effort during an outage, directly contradicting the core requirement.

1. Amazon S3 User Guide - Replicating objects: "Amazon S3 Replication is a fully managed, low-cost feature that replicates objects between S3 buckets... S3 Replication provides an automated mechanism for copying objects." This source validates the use of S3 Replication as a managed, automated solution with low overhead.

2. Amazon CloudFront Developer Guide - Optimizing high availability with CloudFront origin failover: "You can set up CloudFront with origin failover for scenarios that require high availability. To get started, you create an origin group with two origins: a primary and a secondary. If the primary origin is unavailable... CloudFront automatically switches to the secondary origin." This confirms that CloudFront with an origin group is the correct managed service for automated failover.

3. AWS Whitepaper: Disaster Recovery of Workloads on AWS: Recovery in the Cloud (July 2021) - Page 18: This whitepaper discusses data backup strategies. It highlights using "Amazon S3 Cross-Region Replication to replicate data to another Region" as a key method for multi-region data resiliency, reinforcing it as a best practice.