An application is deployed in two AWS Regions, and each Region stores objects in a local Amazon S3 bucket. Both deployments require access to all objects and metadata from both Regions. Two-way replication is configured between the buckets and S3 Replication metrics are enabled. Implement a mechanism that retries replication for objects that fail to replicate. Which approach satisfies this requirement?

The correct approach leverages S3 Batch Operations, which is designed for large-scale object operations, including retrying failed replications. When S3 replication fails, S3 event notifications can trigger a Lambda function. This Lambda function can then initiate an S3 Batch Operations job, providing it with a manifest of the failed objects (identified from the event notification) to retry the PutObject operation to the destination bucket. This is efficient for handling multiple failed objects. Incorrect options: The first and third options suggest using a Lambda function to download and PutObject for each failed item individually. While technically possible, this is inefficient for a high volume of failures and doesn't scale as well as S3 Batch Operations. The second option uses SQS, which adds unnecessary complexity and an additional component for polling, when S3 event notifications can directly invoke Lambda. It also shares the same inefficiency of individual PutObject calls as the first and third options.