Introducing Windows Server 2019 domain conroller in Windows 2008 32bit environment

Question

Planning to introduce Windows Server 2019 in Windows Server 2008 32bit Domain environment.
We're already on DFS-R & on Windows 2008 Domain Functional level. So we're good that way.
Since we know once I introduce a 2019 DC in 2008 environment my schema version will change to '88' which corresponds to Windows Server 2019.

Question:- What shall be my back out plan in case anything goes wrong during the introduction of Windows Server 2019 as a DC since I see that'll update the Schema version itself.
As I'm reading only way to go back to old schema version is a forest recovery.
Does that mean forest recovery is my only backout plan or let me know if there's any other backout plan I could use?
If it's only forest recovery, can someone direct me to the correct steps for backup & restoration of same

Answer 1

The two prerequisites to introducing the first 2019 domain controller are that domain functional level needs to be 2008 or higher and older sysvol FRS replication needs to have been migrated to DFSR
https://techcommunity.microsoft.com/t5/Storage-at-Microsoft/Streamlined-Migration-of-FRS-to-DFSR-SYSVOL/ba-p/425405

I'd use dcdiag / repadmin tools to verify health correcting all errors found before starting any operations. Then stand up the new 2019, patch it fully, license it, join existing domain, add active directory domain services, promote it also making it a GC (recommended), transfer FSMO roles over (optional), transfer pdc emulator role (optional), use dcdiag / repadmin tools to again verify health, when all is good you can decommission / demote old one.

Beyond this if there's some other concern I'd suggest a full backup before hand.

--please don't forget to Accept as answer if the reply is helpful--

Answer 2

If there's some concern beyond what I mentioned I'd suggest taking a full backup before hand.

--please don't forget to Accept as answer if the reply is helpful--

Answer 3

Not sure what you expect to happen. As long as health is 100% before beginning I wouldn't expect problems. Whatever issues should be limited to the domain in question. Might want to test in an isolated environment as first step if there's some concern.

Also verify system and servicing health by running (Server 2008 was notorious for corruption);
sfc /scannow

also system update readiness tool

https://www.catalog.update.microsoft.com/Search.aspx?q=kb947821

Then check for errors in;
%SYSTEMROOT%\Logs\CBS\CheckSUR.log

--please don't forget to Accept as answer if the reply is helpful--

Answer 4

Hi,
For Active Directory Forest Recovery Guide, you can refer to the following link. This guide contains best-practice recommendations for recovering an Active Directory® forest:
https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/manage/ad-forest-recovery-guide

Best Regards,