Replication Issues

Replication Events

To see when replication starts and finishes, increase the 5 Replication Events value under the HKLM\SYSTEM\CurrentControlSet\Services\NTDS\Diagnostics key to value 2, and use Event Viewer. If you set this value to 4 or 5, you can see the names of attributes that have been replicated.

Replication Latency Interval

By default, a DC waits for replication with its partners during a latency interval equal to 24 hours. If a DC does not respond during that period of time, a replication error event will be registered. To change the default latency interval, modify the HKLM\System\CurrentControlSet\Services\NTDS\Parameters\Replicator latency error interval (hours) registry value.

Normal Intra-Site Replication Intervals

If a DC updates an object attribute, it will send a notification message to its first replication partner within a specified time interval (5 minutes by default). To change the default setting (300 seconds), modify the Replicator notify pause after modify (secs) value under the HKLM\SYSTEM\CurrentControlSet\Services\NTDS\Parameters key. The originating DC will notify the next replication partner within the time specified by the Replicator notify pause between DSAs (secs) registry value (30 seconds by default). These values affect replication of all partitions.

To change settings for a specific partition (e.g., for an application directory partition), use the corresponding crossRef object in the CN=Partitions,CN=Configuration, DC=ForestDnsName container:

• The msDS-Replication-Notify-First-DSA-Delay attribute specifies when the DC will notify the first replication partner (5 minutes by default).

• The msDS-Replication-Notify-Subsequent-DSA-Delay attribute specifies when the DC will send subsequent notifications to the second, third, and any other replication partners (30 seconds by default).

Replication to Global Catalog

To enable/disable an attribute to be replicated to Global Catalog, find the corresponding attribute object in the Schema partition and set the value of its isMemberOfPartialAttributeSet attribute to TRUE or FALSE (default settings is <Not Set>, i.e., FALSE).

Intervals at Which the Knowledge Consistency Checker (KCC) Runs

The KCC evaluates the replication topology every 15 minutes (900 seconds) and makes changes as necessary. To change this interval, modify the REG_DWORD Repl topology update period value under the HKLM\SYSTEM\CurrentControlSet\Services\NTDS\Parameters key and set a new number of seconds.

Disabling the Knowledge Consistency Checker (KCC)

To disable automatic generation of replication topology for a site, you can modify the options attribute of the CN=NTDS Site Settings,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=ForestDnsName object:

• To disable intra-site topology generation, set the attribute to 1 (0 × 1)

• To disable inter-site topology generation, set the attribute to 16 (0 × 10)

• To disable both intra-site and inter-site topology generation, set the attribute to 17 (0 × 11)

In a Windows .NET environment, you can also use the repadmin /siteoptions command (to see the command parameters, enter repadmin /experthelp at the command prompt).

To verify replication topology, use the ReplMon.exe utility and generate a report on the site configuration.