Distributed File System Replication

When an Active Directory domain exists, standalone and domain-based DFS namespaces support the replication of DFS data stored on multiple servers. This can be a valuable tool used to distribute company applications to each site or to provide centralized storage of remote office data for redundancy, centralized backup, and to support users who travel and work in different offices.

With the release of Windows Server 2003 R2 and further improved in Window Server 2008 R2, a service to extend the functionality and optimize DFS Replication has been created. This service is called the Distributed File System Replication (DFSR) service, which utilizes the new Remote Differential Compression (RDC) protocol. DFSR replaces the legacy File Replication Service (FRS) that was previously used to replicate DFS data. As long as all of the DFS servers defined in a DFS replication group are running Windows Server 2003 R2 or later, the DFSR service will be used to replicate the data. If any of the systems are running a previous version operating system, DFS data will be replicated using the File Replication Service. There is one exception to this rule: The Domain System Volume (SYSVOL) will be replicated between domain controllers using the File Replication Service, even if all the domain controllers are running Windows Server 2008 R2, until the domain functional level is raised to the Windows Server 2008 level and the SYSVOL is migrated from FRS to DFSR.

DFS Replication and DFS namespaces are independent of one another, but they can be used together, as they are commonly deployed in this fashion. Replication of folders can be set up between servers that do not host any DFS namespaces or namespace folders but the DFS Replication service must be installed on all systems participating in the replication. Windows Server 2008 R2 increases DFS Replication security and performance because all DFS Replication is compressed and encrypted. Note that the data stream cannot be set to run unencrypted.

Source of Information : Sams - Windows Server 2008 R2 Unleashed (2010)