As far as I can tell, there isn't anywhere on Microsoft's sites or documentation which state DFS + Bitlocker is supported or works in Windows Server 2008. The DFSR FAQ mentions DFSR does not work with EFS, but does not mention Bitlocker. This is the case more than likely due to Bitlocker being so far below any user-mode application that the applications (such as DFSR) simply do not know that it exists. Consequentially, testing is not needed for every single scenario of Bitlocker + <app>. Microsoft does officially support the DFSR + Bitlocker combination on Server 2008.
Ned Pyle, a Microsoft enterprise support engineer, volunteered to do some performance testing of Bitlocker + DFSR. The net result was Bitlocker+DFSR worked great. However, there was a ~%25 degraded performance in replication time with Bitlocker turned on. This is to be somewhat expected due to the overhead of encryption, however, having a faster disk subsystem than what was tested with will more than likely significantly improve performance with Bitlocker enabled and reduce this gap. Again - please keep in mind this is a worst-case scenario considering the given hardware and configuration.
Here are the detailed results from the testing:
Sample data: 5.05 GB (5,432,323,831 bytes) Data set made up of: 2008 platform sdk, office 2007, visual studio 2008, r2 sdk, vista sdk directories 51,614 files, 5,680 folders
Bitlocker off: baseline1 - 0h:50m:29s baseline2 - 0h:49m:51s baseline3 - 0h:50m:44s avg - ~50m
Bitlocker on: bitlocker4 - 1h:05m:14s bitlocker5 - 1h:07m:25s bitlocker6 - 1h:06m:10s avg - ~66m (~25% slower)
Hello, everyone Below you have a compilation of some very interesting blog posts from AskDS and Extreme
Interesting, what software do you use to measure?
Check out the following posts: What is the purpose of the 'Deleted' folder in DFSR? DFSR and
The timing for the test was done manually, no special tools were used.