https://aws.amazon.com/blogs/aws/new-replication-for-amazon-elastic-file-system-efs/
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Once configured, replication begins immediately. All replication traffic stays on the AWS global backbone, and most changes are replicated within a minute, with an overall Recovery Point Objective (RPO) of 15 minutes for most file systems. Replication does not consume any burst credits and it does not count against the provisioned throughput of the file system.🔸
EFS tracks modifications to the blocks (currently 4 MB) that are used to store files and metadata, and replicates the changes at a rate of up to 300 MB per second. Because replication is block-based, it is not crash-consistent; if you need crash-consistency you may want to take a look at AWS Backup.🔸
You pay the usual storage fees for the original and replica file systems and any applicable cross-region or intra-region data transfer charges.#EFS
