Looking for upgrade path from 2000 domain to 2003

Question

Windows 2000 Domain, we want to upgrade it to 2003. Once domain is on 2003 we want to put a 2012 member server running SQL 2012 and also keep the 2 demoted Windows 2000 Servers.

3 Windows Servers SP4 32-bit DCs

1. has DHCP and DNS (Schema Master, Domain Naming Master, RID Master and PDC Emulator, Global Catalog)
2. has Printers and Files on it, not worried about these (Infrastructure Master)
3. Windows server 2000 SP4 running Exchange 2003.
4. Windows server 2003 Standard SP2 64bit which runs Sharepoint Services.
5. Windows server 2003 Standard R2 32bit runs SQL 2005

Could either of the existing 2003 servers be used as the new DC, or would it be best to obtain a fresh server as the DC?

Would upgrading the domain have an impact on the 2000 server running Exchange 2003?

Answer 1

The complete answer to your question is really hire a consultant, or more likely, a team of consultants, who've done this before and overhaul your infrastructure to something modern and something "properly" configured, but a few things leap out at me that you really need to know.

1. "Upgrading a domain" is properly termed "raising the functional level," and in a single-domain forest like I'm assuming yours is, you want to raise the functional level of both the domain and forest functional levels at the same time, and to the same level.

   • Your Functional Level can be elevated as high as the Domain Controller(s) with the oldest OS on them. So, if you have a Windows 2003 Domain Controller, the highest you can go would be a 2003 Functional Level. If the Domain Controller with the oldest OS is running Windows Server 2008, you can go to a 2008 FL domain (and so on). It's not an automatic process, but it is a fairly trivial one to perform.

   • The general process for raising the forest or domain functional level is to replace DCs running older OSes with DCs running newer OSes. The easiest way to do this is simply add new Domain Controllers on a higher OS level, and once you have them up and running, demote the old Domain Controllers. If you're strapped for hardware, you can do an in-place upgrade of a Domain Controller to a newer OS, under certain circumstances, and here's the technet page on upgrading existing DCs to Server 2008 R2, but it's generally more trouble that it's worth, and not as clean as simply adding a new server on a higher OS level and promoting it to a Domain Controller. Only do an in-place upgrade of a Domain Controller if you don't have the option to add a new server.

2. It is best not to run additional services on your Domain Controllers, with the exception of DHCP. I personally prefer not to even run DHCP on my Domain Controllers, but many people do without issues.

   • As pointed out by at least a couple other people here, at a minimum, do not attempt to promote a server running other services to a Domain Controller. This will do nothing but cause you pain and problems.
     
     

3. You do not want to keep your demoted Windows 2000 Servers. Windows 2000 is out of support. If you decided to keep the server hardware running Windows 2000, you want to at least upgrade or rebuild them with a supported OS.

4. You do not want to upgrade to Server 2003 at this point in time. It's almost out of support itself, and most everything these days is built for compatibility with Server 2008 R2 and up. If you can't upgrade/replace to Server 2008 R2 (because your hardware only support 32 bit OSes, for example), you want to move to Server 2008. If you upgrade to Server 2003 now, you'll probably be doing this whole thing all over again in a year or two. Best to upgrade once, to Server 2008 or higher than go through upgrading twice in short succession.

5. You also want to upgrade your Exchange Server. Raising the Functional Level of your domain won't impact your existing Exchange server, but Exchange Server 2003 is also falling out of support soon - Exchange 2003 extended support ends on April 8th, 2014 - and newer versions of Exchange are just massively better and easier to manage and administer anyway, not to mention that compatibility with Exchange 2003 is fading fast as well. For how (relatively) easy and cheap an Exchange migration is, I can't see any justification for sticking with Exchange 2003 these days.

Answer 2

It would really be best if you didn't promote a server running existing services to a domain controller (DC). You run the risk of "breaking" the current services the machine hosts w/ the security-related changes that are made during promotion, and it's generally not considered best-practice to host other services on a DC.

You really need at least two DCs for redundancy (and to make your life a lot easier in the event of a catastrophic failure of one of the DCs). You should plan on having two. You don't necessarily need to use a server-class machine for your second DC, but you really should have one.

There will be no operational impact to Exchange re: adding a Windows Server 2003 DC. The AD schema has actually been upgraded to a post-Windows Server 2003 level already since you're running Exchange 2003. The functional level changes won't have an effect on Exchange.