Newb question:

I have two servers, call them OLD and NEW, on a domain that are apparently replicating Active Directory just fine.

The last time I had this setup it was to migrate from 2000 to 2003. I had to do the whole "create BDC, promote, disconnect old PDC (now a BDC)" thing.

This time I'm just going from 2003 to 2003 on different hardware. Now that they're replicating, do I just down the old server?

(Thanks for the help, it's hard to google things when you don't know the current and/or proper terminology to describe what you're trying to do.)

  • 3
    Might I gently suggest that you buy some books on the topic, posthaste. The fact that you're calling your servers PDC and BDC in 2010 is giving me goosebumps. To explicate : not since NT 4.0 domains have there been PDC and BDC, there are only DCs in Active Directory. There is a FSMO role called PDC emulator, but for day-to-day stuff, it's no more important than any other DC. On-topic: If the old server is reliable, leave it there and just add the new server and DCpromo it. You generally want to have redundant DCs in a domain.
    – mfinni
    Feb 22, 2010 at 20:02
  • Thanks for the advice. We generally just run one server, it's a very small shop, and I thought (since we still have some older client hardware running Win98) that being in compatibility mode they were still called that when I did the migration in 2006. Also, the old server is on its last legs...
    – Kev
    Feb 22, 2010 at 20:13
  • @Kev: If you have the Windows Server license laying around I would keep the old computer running as a domain controller and doing nothing else. It's a very cheap "insurance policy". Disaster-recovery of AD w/ a single domain controller isn't much fun. Having a replica DC around makes life a lot easier if disaster strikes. Feb 26, 2010 at 19:52
  • It's "cheap" except that it needs new parts--we just had a drive fail on it yesterday. I wasn't kidding about last legs... Also I don't have an extra license, just the original, so I technically shouldn't run both of them at the same time.
    – Kev
    Mar 2, 2010 at 13:54
  • @mifinni, just a follow-up, I noticed the term 'PDC' in my event log this morning, and MS still uses the term in articles such as this one: support.microsoft.com/kb/816042 (And the Applies To list has Win2003 as the oldest version...)
    – Kev
    Mar 2, 2010 at 13:56

1 Answer 1


If you run dcpromo on the old DC and demote it, the dcpromo process will transfer the FSMO roles to the new DC. Make sure to update your clients to use only the new DC for DNS if the new DC will be the only remaining DC\DNS server.

  • Ah, so you do still have to demote, it's not like a multi-master mirror. Thanks! And I assume I'd update the clients by just changing DHCP settings...
    – Kev
    Feb 22, 2010 at 19:49
  • 2
    Yes, running dcpromo to demote the old DC will remove it from AD and DNS and transfer the FSMO roles to the remaining server. Modifying your DHCP accordingly will take care of the clients.
    – joeqwerty
    Feb 22, 2010 at 19:52
  • Also, if you simply shut off the old DC then you'd have to manually remove it from AD and DNS, which is a pain. Dcpromo is the "graceful" way of removing a DC.
    – joeqwerty
    Feb 22, 2010 at 20:02
  • 1
    @mfinni: The process of running dcpromo on the old DC will demote it back to being a member server, remove it from AD as a DC, remove it's SRV records from DNS, and transfer any FSMO roles it has to another DC. IMHO, dcpromo is the preferred method of removing a DC.
    – joeqwerty
    Feb 22, 2010 at 20:06
  • 2
    You actually should demote otherwise you'll still have an orphaned DC in your AD (single master vs multi master doesn't come into it). You can of course just power it down and use NTDSUTIL to remove the orphaned DC, but that should not be used unless you have no other option (e.g. catastrophic hardware failure and no backup, or some idiot just powers it down). Demote is the graceful way to go. Feb 22, 2010 at 20:35

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