SYSVOL FRS to DFS-R Migration

Microsoft just released a guide on how to migrate from using FRS (File Replication Service), to using DFS-R (Distributed File System Replication) for the SYSVOL folder. Since DFS-R offers more performance, scalability and reliability, migrating to DFS-R for SYSVOL is very beneficial. Sander wrote the following stuff on his blog about the guide.

You can download the Migration Guide here.

About SYSVOL and SYSVOL replication

Domain controllers use a special shared folder named SYSVOL to replicate logon scripts and Group Policy object files to other domain controllers. Windows 2000 Server and Windows Server 2003 use File Replication Service (FRS) to replicate SYSVOL, whereas Windows Server 2008 uses the newer DFS Replication (DFS-R) service when in domains that use the Windows Server 2008 domain functional level, and FRS for domains that run older domain functional levels.

To use DFS Replication to replicate the SYSVOL folder, you can either create a new domain that uses the Windows Server 2008 domain functional level, or you can use the procedure that is discussed in the Migration Guide to upgrade an existing domain and migrate replication to DFS Replication.

About the Migration Guide

The SYSVOL Replication Migration Guide details the steps to perform to migrate from FRS replication to DFS Replication. (DFS-R) The tool used is dfsrmig.exe, which guides you through three states:

  • The Prepared State
    The Prepared state configures the DFS Replication service to replicate a copy of the original SYSVOL folder. When all domain controllers reach the Prepared state, DFS Replication is properly configured and it has completed an initial synchronization. In the Prepared state, the replication of the SYSVOL shared folder still depends on the File Replication Service (FRS).
  • The Redirected state
    In the Redirected state the live SYSVOL share (mapped to the old SYSVOL folder that FRS replicates) is mapped to the new copy of the SYSVOL folder, replicated by the DFS Replication service. From this point onward, SYSVOL replication depends on DFS Replication.
  • The Elimated state
    At the end of the Elimated state, the FRS SYSVOL replica set and the old SYSVOL folder are deleted. Not only does SYSVOL replication depend on DFS Replication; all remnants of SYSVOL FRS replication are gone.
  • Of course the guide goes into detail on verifying states, verifying Active Directory health, rolling back failed steps, troubleshooting migration issues, transitioning management and of course contains a command reference for dfsrmig.exe.

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