Cause: Monitor replication regularly to help identify and fix problems before they grow.
Solution: Regular monitoring is the key to good replication maintenance. You can use Repadmin.exe, Dcdiag.exe, and the Directory Service event log (in Event Viewer) as your primary tools for monitoring replication.
Repadmin is a command-line tool that reports failures between two replication partners. The following repadmin example displays the replication partners and any replication failures for Server1 in the adatum.com domain:
repadmin /showrepl server1.adatum.com
For a complete list of repadmin options, use the ? option:
Dcdiag is a command-line tool that can check the Domain Name System (DNS) registration of a domain controller, verify that the security identifiers (SIDs) on the naming context heads have appropriate permissions for replication, analyze the state of domain controllers in a forest or enterprise, and more. The following dcdiag example checks for any replication errors between domain controllers:
For a complete list of dcdiag options, use the ? option:
The Directory Service log (in Event Viewer under Application Logs) reports replication errors that occur after a replication link has been established.
Replication between sites is slow.
Cause: The time that is required to replicate directory data between domain controllers is known as the replication latency. Replication latency can vary greatly, depending on the number of domain controllers, the number of sites, the available bandwidth between sites, replication frequency, and more.
Monitoring replication regularly is a good way to determine the normal replication latency on your network. With this knowledge, you can more easily determine if a problem is occurring.
Review the Directory Service log for any recent replication errors. Also, run the repadmin /showrepl command, and review any resulting errors.
A good site topology design is important for replication efficiency. For information about site topology design guidelines, see Designing the Site Topology for Windows Server 2008 AD DS (https://go.microsoft.com/fwlink/?LinkID=93576).