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Both of my domain controllers are on Server 2012R2. These servers are also my DHCP and DNS servers. The main DC is mirrored to the backup DC.
I have licenses to upgrade both servers to Server 2022. My question is, can I upgrade from 2012R2 to 2022? And, can I upgrade the backup DC first, then promote it to main then upgrade the other DC and start the replication again?

I also have two VM’s configured to also be replication servers for the DCs. Should I promote a VM DC then upgrade a physical server? Not sure the best way to do this. I know inplace upgrades of a DC is not recommended, but everything I’ve read says it works fine with Server 2022. And besides, I have other DCs ready incase I need to do a fresh install of the OS.

7 Spice ups
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do not upgrade DCs. build new, let replicate, demote old.

10 Spice ups
3

Build 2 new VMs, make them DCs, transfer your roles, allow time (days) for syncs, move your FSMO roles, update DHCP scopes to use new DCs as DNS, demote old.

2012 to 2022 is not a supported direct upgrade path, anyway, but upgrading a DC is not recommended.

See here for a similar situation.

Windows Server 2025 - Upgrading hell! - Windows - Spiceworks Community

Do bear in mind, you may also need to upgrade DFS to DRFS if this is not already the case.

5 Spice ups
4

+1 for build new.

EDIT: a friend did me the favor of upgrading 5 domains from 2008 to 2012 and had a much easier go of it with the new 2019 VM builds when upgrading again from 2012 to 2019. I don’t see him choosing any other method for next round.

1 Spice up
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Thed two VMs I currently have are server 2019 and Server 2022, and neither will replicate with a 2012 server. You’re saying spin up two servers running 2012, replicate them and promote them as DCs. Then completely wipe the physical server and install 2022? I can do that but how do I get the 2012 VM DC to replicate with the new 2022 DC? Is there a greater version of Server OS that 2012R2 will replicate with? I was thinking maybe I could install an eval copy of Server 2019 if that would work?

1 Spice up
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I was under the impression you could still go from 2012 to 2019 as long as the 2012 AD forest and domain were at the highest supported for that version.

EDIT: So my assumption is that it would be fine to promote the 2019 server to domain controller then demote the non FSMO 2012 server. Then take FSMO roles with the 2019 server. Then you could promote the 2022 server and demote the remaining 2012 server. Or something very close to that.

1 Spice up
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Has to be 2008r2 min, then it is at least possible.
But…there are a bunch of other things you have to fixup first…
Make sure you don’t have any pending failed GPO’s
Make sure the 2 existing machines are totally happy (sync) with each other,
you are going to stress them out when you add the 3rd machine…
Make sure the 2012 machines are patched to the very last patch level, there
was a hotfix for a bug in GPO versioning that will break sync with 2019,
it doesn’t break anything in the 2012 environment, so it is invisible until you start
the migration.

1 Spice up
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Your first post doesn’t say this.

The 2019 and 2022 DCs, are these in the same domain?

Are you pointing each DC at another first?

Nope, you said you have 2 2012 DCs, we’re advising you to create new VMs and replicate FROM the 2012 DCs.

Don’t install evals and I’m not saying it wont replicate, I am saying don’t upgrade them as this comes with hell.

If this isn’t something you are comfortable with, get someone in to do it for you. Your domain is your business, if it’s down, you have no business.

2 Spice ups
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All of the above. I believe you have to upgrade your 2012 AD (functional level) to 2016 AD (functional level) first in order to upgrade AD to 2022 (functional level.) That is, spin up probably two 2016 VMs and promote to DC, move FSMO roles. Upgrade AD functional level to 2016. Demote and retire 2012 Dc’s. Spin up 2022 VMs/Physical boxes (VMs are usually better,) promote to DC’s and move FSMO roles, upgrade AD functional level to 2022. Demote and retire 2016 DC’s.

1 Spice up
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There is no 2022 functional level, it’s 2016 and nothing until 2025

1 Spice up
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Have you migrated the DC2012R2 to using DFSR ?
What is the current Domain Function Level ? It have to be server 2012r2 at least.

The DC2019 & DC2022 cannot replicate ? How did you manage to discover this ?

  • Are all of the 4 DCs have records in all of the DNS servers ?
  • Did you set the 4 DNS server IPs in all the 4 servers (you need to change the server 2019 & server 2022 BEFORE promoting to DC) ?
12

I stand corrected. 2022 can technically run 2025 AD (FL) though.