You can't configure DFS-R on a Multi-AZ or Single-AZ 2 file system - Amazon FSx for Windows File Server
Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China.

You can't configure DFS-R on a Multi-AZ or Single-AZ 2 file system

Microsoft Distributed File System Replication (DFS-R) is not supported on Multi-AZ and Single-AZ 2 file systems.

Multi-AZ file systems are configured for redundancy across multiple access zones natively. Use the Multi-AZ deployment type for high availability across multiple Availability Zones. For more information, see Availability and durability: Single-AZ and Multi-AZ file systems.