First published on TechNet on Apr 22, 2010
here again. Recently I was asked to provide a technical assessment of the risks of continuing to use the File Replication Service (FRS) and the benefits of migrating to DFSR, all regarding SYSVOL on domain controllers. I thought I’d find a decent set of documentation on TechNet, polish it up and send it along – I was wrong; I had to spend several hours coming up with a complete list.
Now you can reap the benefits. Hopefully this helps you convince yourself or your management that the time has come to cut the cord on FRS, especially if you have already deployed your Windows Server 2008 DC’s.
I sure hope you like bullet points!
The risks and downsides of FRS and SYSVOL
FRS code is in maintenance mode
, where Microsoft does not accept design change requests or bug fixes except when related to security.The last FRS bug fix update was released in KB939667. It was for Win2003 and nearly 3 years ago; Win2008 has never gotten an FRS bug fix update in its history.
Additionally, the FRS component began deprecation starting in Windows Server 2003 R2:
The Microsoft product team stopped investing in FRS in Windows Server 2003 R2, when it was decided to build DFSR and have that replace FRS even for SYSVOL replication
DFSGUI.MSC FRS management tool was removed in Win2008
FRS component no longer installable in Win2008 R2 except for SYSVOL replication on DC’s
FRS component automatically uninstalled during in-place upgrade of Win2008 R2 non-DC’s
FRS scalability and performance are
than DFSR, especially with frequently modified files, larger data sets, larger files, and slow wide area networks. FRS always replicates an entire file regardless of modification type (i.e. a security change, data change, attribute change, or file name change each replicate the entire file)
FRS does not include a public development interface (API or WMI) for monitoring, and it’s interface for management is limited
FRS does not have a native, supported health reporting mechanism.
FRS does not have a native, supported monitoring solution from Microsoft System Center. Only has legacy unsupported tools like Sonar, Ultrasound, CONNSTAT, etc. with limited MOM 2005 integration
FRS has limited performance monitoring counters through PERFMON/ETW
DFSR has a self-healing system for problems like database corruption or journal wraps. Due to improved replication performance and the ability to enable content freshness protection, it is also very unlikely to ever see a journal wrap in the first place. DFSR also does not create morphed folders like FRS and instead uses a
conflict resolution algorithm
DFSR supports RODC SYSVOL replicas and does not allow SYSVOL’s to remain out of sync in Win2008. In Win2008 R2 originating I/O in SYSVOL is completely blocked with
a filter driver on RODC’s
DFSR - while it does not directly support the AD DS
inter-site change notification flag
– always replicates SYSVOL immediately and continuously with its own internal change notification as long as the schedule is open; these scheduled windows are in 15 minute blocks and are assigned on the AD DS connection objects. If the current time matches an open block, you replicate continuously (as fast as possible, sending DFSR change notifications) until that block closes. If the next block is closed, you wait for 15 minutes, sending no updates at all. If that next block had also been open, you continue replicating at max speed.
DFSR has significant built-in instrumentation for troubleshooting and debugging, including considerable event logging and a large number of
highly verbose debug logs
(1000 debug logs maintained under compression by default in Win2008 R2, at the second to highest level of verbosity by default)
Here’s a different way of looking at it, as I know executives love their matrices:
Reliable, fast, scalable, and continually improving
Is deader than fried chicken
Now go migrate
. For most customers it will be a few hours of work. Your manager may not even have time to buy you lunch on a Saturday.
Stay tuned for another article about the benefits of using FRS. Its title will be “the shortest blog post ever written” and will contain only a picture of my dogs eating their toys. Here’s a preview.