In Star Wars, “R2-D2” was Luke Skywalker’s good friend. If you’re running a domain with FRS, D2 is your good friend. Even thought (2008) R2 (and DFSR) should be your buddy.

So when should you call your D2 buddy and give him a run?

You experience:

• One of your DCs are in Journal Wrap
• The local FRS jet database has become corrupt
• Assertions in the FRS service
• Missing FRS junction points
• Missing FRS attributes/objects
• Missing SYSVOL/NETLOGON share
• Corrupt/missing NTFS journal
• You are bored… (meaning the list is long)

Setting the backup/restore flag , a.k.a. “Burflags”, to D2, and you restart the NTFRS service things start moving.

HKLM\System\CurrentControlSet\Services\NtFrs\Parameters\Backup/Restore\Process at Startup

The bad DC will move all its SYSVOL data, if it holds any, into the “NtFrs_PreExisting_See_EventLog” folder. The bad DC will compare all these files with the ones of an upstream partner. It will compare the file IDs and the MD5 checksum from the upstream partner with the local ones. If a match is found, it will copy this file from the Pre-Existing folder into the original location. If it don’t match, it will copy the file from its partner.

When the replication has finished (Event ID 13516 is logged), you can delete the content in the Pre-Existing folder to free up space.