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DFSR guru question - crash recovery

Posted on 2013-01-22
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Last Modified: 2013-01-22
EE,

The other day we experienced a network outage that caused our DFSR 2008 R2 infrastructure to crash hard.  After bringing the systems back online, DFS replication did not begin for hours though no matter what we did we could not see any problems in the logs.  We sat and waited for maybe 8 hours and even though replication and health checks passed and we could find no DFSR specific events in the logs and replcation would not continue.  Over night, magically, it began again.  This lead us to the conclusion that what it was doing during the long pause before replication began was comparing every file with its replication partner and learning if there were changes or not that needed to be replicated.  It needed to start from scratch because of the crash; it didn't know where it had left off.

My question is, does this sound like the correct assessment of the cause for the replication delay and do you know of a way to expose logging or event messages that would warn us in the future that this "start from the beginning comparison" process is in progress?
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Question by:JohnDemerjian
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“When the DFS Replication service is asked to resume replication and perform unexpected shutdown recovery, either via auto-recovery or via manual intervention, it performs the following steps:

1) The first thing that DFSR does is to validate if the “USN checkpoint” in the database is valid by comparing the database against referenced USN record in the journal. If the checkpoint itself is invalid, each entry for each file and folder in all replicated folders on the volume is examined for correctness by comparing the entry to the corresponding file or folder on the volume. So this could take some time, depending on how many files are in the replicated folder(s).”

http://blogs.technet.com/b/filecab/archive/2012/07/23/understanding-dfsr-dirty-unexpected-shutdown-recovery.aspx
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