I have 2 empty root Domain controllers still running Server 2003.  One is physical, running Server 2003 R2, 32bit.  I didn't think that was possible because I though all R2 versions had to be 64bit.  I guess that started with Server 2008 R2.  The other DC is a virtual server running Server 2003 SP2(also 32 bit).  The physical server holds the Domain naming operation master role.  The Virtual server holds the Schema Master role.  

Ideally I would like to get them both to 64 bit OS and preferably both to Server 2012 R2.  I figure I will put up a new 2012 R2 virtual Server and promote it to DC.  I'm a bit unsure of the role migration process.  More specifically, Is there a proper order to follow? Schema master first...etc

Is it simpler to upgrade them in-place and keep them at 32 bit since my child domain is already at 2012 domain functional level?

Hi

 First you need to upgrade server 2003/R2 DCs to sp2,

And then add Windows server 2012 r2 as an additional domain controller,transfer fsmo roles to server 2012 r2.Finaly demote server 2003 DCs from domaib.will do metadata cleanup,make sure All AD DS,DNS,AD site and sercies,DFS updated.

Check these step by step miration guides also;

http://blogs.technet.com/b/canitpro/archive/2014/04/02/step-by-step-active-directory-migration-from-server-2003-to-windows-server-2012.aspx

https://blogs.msmvps.com/mweber/2012/07/30/upgrading-an-active-directory-domain-from-server-2003-or-windows-server-2003-r2-to-Windows-server-2012/

• Edited by Burak Uur 16 hours 51 minutes ago Add link

"R2"  it's just a part of the name of the OS, it has nothing to do with the architecture. Starting with Windows 2008 R2 all the server OSs are x64, so you cannot upgrade 32 bit systems to 2012.

To buy myself time, I can do an in-place upgrade to Server 2008, correct?

You can migrate from 2003 to 2012r2 check the articles on my previous message.

Before upgrading, make sure that all your AD-Integrated systems and applications are compatible with DCs running Windows Server 2012 R2. If this is the case then you can do your upgrade. You can simply introduce DCs running Windows Server 2012 R2, make them DC/DNS/GC servers, transfer FSMO roles and demote the old DCs.

You need also to make sure that no application is hardcoding your existing DCs IP address or host name for LDAP querying. If this is the case then you need to think about the downtime which can be caused by the upgrade operation. Also, you might think about re-using old IP addresses for your DCs so that you don't have to manually update systems with static IP settings. A final thing to think about is that you need to make sure that DNS servers IP addresses in your DHCP scopes are well configured after the upgrade.

Burak,

The link you sent are broken, I think that when he says inplace upgrade he is talking about the OS and that cannot be done.