Wednesday, July 27, 2011

How to read the result of repadmin /replsummary

Repadmin helps administrators diagnose Active Directory replication problems between domain controllers running Microsoft Windows operation systems.

You can use Repadmin to view the replication topology, as seen from the perspective of each domain controller.

In addition, you can use Repadmin to manually create the replication topology, to force replication events between domain controllers. You can also use Repadmin to monitor the relative health of an Active Directory Domain Services (AD DS) forest.

1. On a domain controller, log in as Domain Administrator.
2. Launch "Command Prompt".
3. Enter "repadmin /replsummary".

The Active Directory replication information was displayed.

By default, the replication model is pull-based in Active Directory, so you should focus on the destination domain controller first.

In the above picture, each dot after the first three represents a domain controller. it isn't more than 50 dots per line.

Largest delta denotes the longest replication gap amongst all replication links for a particular domain controller.

Total is the replica links for a particular domain controller (one for each naming context on each domain controller). Please note that this is not the connection objects or replication partners per domain controller. I will enter the other command to show it.

Fail is the total number of replica links failing to replicate for one reason or the other. This will never be greater than the Total field.

Percentage is the percentage of failures in relation to the total replica links on the domain controller.

Now, we don't know the replication information of the current domain controller. I have to enter the following command:

4. Enter "repadmin /replsummary %computername%".

Now, the current domain controller is DC11 and it pulls the replication information from other source DCs.

5. I want to get the replication information of  DC04, enter "repadmin /replsummary dc04".

The replication information of dc04 pulls from DC11.

6. Enter "repadmin /showrepl dc04" to show the total replication link.

There are 5 replica links for replication. In DC11, there are 45 replica links because it needs to pull all other domain controllers.

To use "repadmin /showrepl", you can verify the largest delta.

The time replsummary taken was 22:08:33. Now,  if you look at the schema naming context replication time, 22:00:44 , the difference is about 7m:, which relates to the largest delta.

I hope I can help you to understand the "repadmin /replsummary" easily.


This posting is provided “AS IS” with no warranties, and confers no rights!


  1. Hi Terry,

    Thanks for taking the time to put this together. I have been working an issue that while small (two)DCs has been exhibiting some strange account lockout and object access errors.

    When I run the rapadmin /replsummary command, the delta is somewhere around 38 minutes.

    Your post (while very informative) does not actually talk the deltas within the context of what is normal or could be expected.

    Is there a threshold that you would consider concerning?

    Thanks again for the great work!



    1. Hello Paco,
      By default, if there is no update in this domain(5 default partition), the intra-replication time is 1 hour. The inter-replication time is 180 minutes in domain controller of Windows Server 2003 or later. I hope this can help you.


  2. Great and easy to understand article about one of the basic AD troubleshooting tools. Thank you!