File Replication Service (FRS) troubleshooting tools

The File Replication Service, or FRS, is a critical component of an Active Directory deployment.  When it has problems, it can be a lot tougher to troubleshoot than basic AD replication.  There are some good Microsoft tools out there that can help.  There are probably good 3rd party and freeware tools too, but these are the ones I am aware of.  It is probably best to start with FRSDiag to get comprehensive information.  Sonar is real useful for monitoring on a repeated cycle.


  • Ntfrsutl Tool.  This built-in utility allows you to see the FRS configuration, view inlog/outlog, list replica sets, examine memory usage, logging, etc.  Documented in the online help.
  • FRSDiag - Sweet utility! FRSDiag provides a graphical interface to help troubleshoot and diagnose problems with the File Replication Service (FRS). FRSDiag works with existing information such as event logs, ntfrsutl, repadmin, etc.  W2K SP3 or newer required.
  • Ultrasound.  Ultrasound is a powerful tool to measure the health of FRS replica sets by providing health ratings and historical information about replica sets. Ultrasound also allows administrators to monitor the progress of replication and detect problems that can cause replication to become backlogged or stopped.  Requires W2K SP3 + hotfix 815473, W2k SP4, or Windows 2003. Also needs a SQL/MSDE database.
  • Sonar.  Sonar is a tool designed for monitoring key statistics about FRS members in a replica set. Sonar can collect basic status information from FRS running on either Windows 2000 (all service packs) or Windows Server 2003. You can use Sonar to easily watch coarse statistics on a replica set, and to monitor traffic levels, backlogs, free space, and other issues.
  • FRS log files. The log files are stored in systemroot\Debug and have the detailed information about FRS activity.  The FRS logging characteristics are configured in the registry. 

Keep in mind too that when you force AD replication using AD Sites and Services, that FRS is not included. With Windows Server 2003 (and a pre-SP1 patch) you can force FRS replication using the "ntfrsutl forcerepl" command.   Patch here:;en-us;823230&Product=winsvr2003