“It’s Simple!” – Do the move! Go to DFSR!

Hi there!

I have noticed the following at many customers who had upgraded their Active Directory from Windows 2000/2003 to 2008 and plus: they do not (or forget to) upgrade Sysvol from FRS to DFSR!

Several Technet articles covered the steps to do for Sysvol migration, so there is no need to go in details here…

“Upgrading to DFSR? What is DFSR? Besides, everything is working fine! Why should I upgrade?”

Those are –very often- the questions and feedbacks I get from customers :)

So here is the thing:

  • Keep in mind that Sysvol is a shared folder (with DFS name space) that needs to be the same copy on each DC,
  • Sysvol is replicated through DCs using File Replication Service (FRS) or Distributed File System Replication (DFS-R),
  • This replication follows the Active Directory replication topology and paths,
  • We have stopped any development on FRS since 2003, which means for example: no updates or hotfixes! On the other side, DFSR is here to stay for a long time (cross-fingers!)
  • FRS is not a bandwidth optimization service, but DFSR is! For example, DFSR replicates partial file changes / efficient compression / self-healing mechanism for database corruption or journal wraps …etc (see the comparison here)
  • DFSR requires Domain Functional Level –DFL for short- of minimum Windows 2008 (how to check and upgrade your DFL here), so you have to review the upgrade possibility in your environment,


All right! I’m planning to do it, what are the actions?

That’s good! Here are the summarized actions for upgrading your Sysvol to DFS-R:

  1. Migrating to the “Prepared state” : FRS is still being used for replication, and DFS-R will hold a copy of your Sysvol data,
  2. Migrating to the “Redirected state” : DFSR-R will be used for replication the ‘copy’ Sysvol, and answering new requests, but FRS is still replicating the ‘old’ Sysvol folder,
  3. Migrating to the “Eliminated state” : no more FRS, only DFS-R is being used for Sysvol replication


Side notes:

  • Required firewall ports for DFS-R here
  • Troubleshooting DFSR upgrades here
  • More info on TechNet  


Hope it’s simple now!


Imed Boukhaf from NEPA team.