Primary Domain Backup Controller

Hello.

I'm going to assume that when you say "PDBC" you actually are talking about the BDC - BackupDomainController.

You will never get the BDC to be identical to the PDC. That is not it's function.

The BDC was meant to provide Domain Authentication, on a temporary bassis, when the PDC is off-line. You cannot Add or change users (UserManager) or other security parameters when the PDC is off-line.

You can promote a BDC to a PDC but only when the PDC is off-line. You can then demoatethe PDC back to a BDC when the PDC comes back.

REF MS KB:
Q167248

Regards
Raffi_

Ouch...PBDC means BDC right !! PDC has to be running all the time when your users are loggin to the domain.
In case you switch off your PDC & your BDC is on, no one gets authenticated.. user cannot login.
In case you switch of your BDC & your PDC is runing, users can login BUT domain sync with not be done.
SO both PDC & BDC have to be running.
Akash

The first answer is incorrect. If you promote the BDC to a PDC when the PDC is offline, you will NOT be able to demote the BDC once the PDC comes back online, you will have to reinstall it as a BDC. What you can do is before you take the PDC offline, go into server manager and promote the BDC to a PDC, it takes a few mins and what actually happens, is the DCs switch rolls, the BDC becomes and PDC and the PDC becomes a BDC. Once it is complete and you verify it is complete in server manager, then you can take your server down. When you are finished and ready to bring the server back online. Bring it online, go into server manager, tell it to synchronize with the PDC, this may take a few mins. You can verify that this is done in the Event log. Once this is done, select the server and promote it to a PDC. It will go through the process again and your original server configuration will be restored. You want to make sure that you have no users online when you do the switch. I have done this, 3 times now, and have had no problems at all. If you have any other questions or concerns about this procedure, please email me. I hope this helps.

Woody