AD - FSMO Role

Question

Hi Guys,

I have AD Server running windows 2012 r2 (FFL/DFL). I'm planning to update 2016.

Can anyone guide me if any prerequisites to validate before update forest and domain function level from Windows Server 2012 r2 to 2016

Thanks in advance.!

Answer 1

The prerequisite before introducing the first 2016 domain controller: domain functional level needs to be 2003 or higher

I'd use dcdiag / repadmin tools to verify health correcting all errors found before starting any operations. Then stand up the new 2016, 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.

Also at some point either before or after I'd recommend migrating (if not already done) sysvol replication from older FRS technology to DFSR
https://techcommunity.microsoft.com/t5/Storage-at-Microsoft/Streamlined-Migration-of-FRS-to-DFSR-SYSVOL/ba-p/425405

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Answer 2

Hi,

Before upgrade the DFL and FFL from windows 2012 R2 to Windows 2016, you have to upgrade all your domain controllers on Windows 2016 if you still have a domain controllers on windows 2012. All domain controllers in your forest must be installed on Windows 2016 or higher to be able to upgrade the domain functional level DFL and forest functional level FFL to windows 2016.

If you are talking about domain controller OS upgrade from windows 2012 to 2016 , with domain controller on windows 2012 R2 , you can promote an additional domain controller on windows 2016 and demote DC windows 2012 because windows 2016 ans Windows have the same prerequisite.

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Answer 3

@Gopi Ponnusamy You can find detailed information, process and requirements here - https://learn.microsoft.com/en-us/troubleshoot/windows-server/identity/raise-active-directory-domain-forest-functional-levels