Jeff Barr 在官方 blog 上宣佈 Amazon EFS 提供 replication 功能：「New – Replication for Amazon Elastic File System (EFS)」。
可以看到跨區的設定畫面：
在建起來以後會是 read-only filesystem：
另外有提供 fail-over 機制，當 fail-over 過去後會從 read-only 變成 read-write。
不過要注意，架構上屬於 eventually consistent，預期是一分鐘內會更新。這點算是可以預期的，不然 latency 會太高：
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.
然後 replication 不會計算到 I/O 的 credit 與 throughput，算是比較特別的一點：
Replication does not consume any burst credits and it does not count against the provisioned throughput of the file system.
replication 這個服務本身不另外收費，只收取 EFS 使用的空間以及 replication 產生的頻寬費用：
You pay the usual storage fees for the original and replica file systems and any applicable cross-region or intra-region data transfer charges.