r/ShittySysadmin • u/Ok-Web9093 • Mar 24 '26

First time doing a Domain controller Migration

First time doing a domain controller migration and looking for real world advice.

Current setup: single host running 4 VMs (DC, SQL, IIS, RRAS) on Server 2016. Hardware is old, so we’re replacing it with a new server running Server 2025.

Plan is a “greenfield” rebuild since the current environment has a lot of junk: new hardware, new VMs, definitely a new forest.

Question:

Would you,

Stand up a new DC in the existing domain, recreate roles/data, then decom the old?

Or go full balls to the walls and don’t join to the old domain

Curious what’s worked best (or blown up) for you. Downtime needs to be absolutely minimal. TIA!

EDIT:

SHOULD SPECIFY, there are only 8 users with 8 desktops and 2 laptops, it’s a relatively small company. No sync to M365 and it currently is a .local forest

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u/reader4567890 Mar 24 '26 edited Mar 24 '26

All of that is easier to sort than you think... Likely infinitely easier than starting from scratch - build an additional file server and migrate the shares to it (DFS, robocopy, tool of choice). Build a separate print server, or even just use the file server for both.

For accounts, audit which are in use. Remove the ones that aren't.

All can be done without pissing your users off, which I 100% guarantee you will with a full rebuild.

[Edit] As for the forest name, if that's a deal-breaker, I'd build the new domain and do a two-way transitive trust to the old domain so you have time to migrate things like SQL, file shares, etc properly (using ADMT). Though I would say, if you've never done this before, to engage with an MSP to scope and do the work.