The Dcdiag tool
The Directory Service Diagnosis tool Dcdiag.exe, performs a number of tests and reports on the overall health of replication and security for Active Directory DS. If you run the tool without any parameters it performs the basic tests and gives you a summary report while with the option /c it runs almost every test. As with most command-line tools you can redirect the results to files of various types including XML formats. If you need to perform specific tests such as, getting errors in the file replication system (FRS), you can use the option /test:Test Name where in this case the Test Name would take the value FrsEvent.
To read more about the Repadmin tool go here.