A data-collection application runs in eu-north-1 and writes processed records to an S3 bucket in eu-north-1 that is queried by Athena. The company is expanding the data-collection capability to sa-east-1 and ap-northeast-1 and deploys the collectors, Kinesis streams, and Lambda processors in those Regions, but keeps the S3 bucket centralized in eu-north-1 for analysis. During testing, data arriving from the new Regions to the central S3 bucket shows significant lag. Which change will reduce that cross-region arrival lag the MOST?

The most effective solution is to create local S3 buckets in sa-east-1 and ap-northeast-1 and use S3 Cross-Region Replication (CRR) to the central eu-north-1 bucket. This minimizes latency for the data collection applications by allowing them to upload to a geographically closer S3 endpoint. CRR then handles the asynchronous, managed transfer of data to the central bucket, optimizing for throughput and reliability over the AWS backbone network, thus reducing arrival lag. Using S3 Transfer Acceleration would improve upload speeds from the new Regions directly to eu-north-1, but it still involves a direct cross-region upload, which can be less efficient than local uploads followed by CRR for consistent, high-volume data. Configuring Lambda in a VPC with an S3 gateway endpoint is for private network access within a Region and doesn't address cross-region latency. Increasing Lambda memory and using multipart uploads might offer minor improvements but won't fundamentally solve the underlying cross-region network latency issue as effectively as local uploads with CRR.