Raising the domain level - can i do this during production

Raising the domain functional level is a very quick process that doesn't require a reboot of any domain controllers. The standard disclaimer* applies, but you shouldn't have any trouble performing this during normal business hours.

If you want to be really safe, do it after hours, but you'll likely be finished before your coworkers are out of the parking lot.

* "You'll have no trouble as long as there aren't any underlying problems with the domain that haven't revealed themselves yet."

IS there anything else i need to do before raising the level.
if an error should occur do it stop it from upgrading

i ran this DCDIAG /C /E /V


Is this what i show look at whether or not i should proceed?

i ran this  dcdiag/test:dns
got the following


how do i resolve this?

It looks like you have serious problems with DNS on one of your DCs. You should start troubleshooting that.  The first thing I'd suggest is rebooting the problem system.  Then start investigating - look for errors in the event logs and research them and correct them.  eventid.net is good but requires a subscription for some of the more detailed info.  You could get a trial I think.

Raising the domain functional level is a very quick process that doesn't require a reboot of any domain controllers.

I have never had to restart any DC's after a functional level change, but I have had to restart the KDC service across all DC's to resolve issues after a functional level upgrade (going 2003 -> 2008 R2). A whole lot of stuff broke which included Exchange. The event logs were filled with Kerberos related errors. Luckily it was done in an out of hours change window, so we restarted the KDC service across all DC's (over 100) which resolved the issue. I see the OP is going from server 2003 DFL to 2008 so the same issue that happened to be will be particularly relevant to them.

https://blogs.technet.microsoft.com/exchange/2015/02/13/considering-updating-your-domain-functional-level-from-windows-2003-read-this/

You are right i am having DNS issues. i cant get into event viewer.if i reboot it just keeps rebooting i cant log into it with another user.
i am having to revert to the last snapshot i took of the VM server. any recommendations on how to resolve?

NO!

You DO NOT use Snapshots on DCs before 2012 and even then I wouldn't do it.  You could corrupt AD worse if you revert to previous snapshot.  DO NOT DO IT.  If you don't understand AD, I strongly recommend you hire a pro who can help you directly.  This is VERY DANGEROUS right now!

i ended up migrating to a windows server 2012. i finally got everything moved over and installed.

i ran this DCDIAG /C /E /V on both servers



i should be ready now to raise the domain functional level, correct.

should i check something else before upgrading it

ok i raised the domain functional level
on the new server 2012R2 i get the following


What does this mean?

and on my server 2008 i get the following

This indicates that you can't raise the functional level beyond Windows Server 2008 because you have at least one domain controller running that version of Windows. The domain functional level dictates the oldest version of Windows that can be run on a domain controller in that domain.

so once i upgrade the server 2008 to server 2012R2 then i should be able to see the other options.
everything should be good now correct.

how would i check to see the new features that come with the 2008 functional level?

so once i upgrade the server 2008 to server 2012R2 then i should be able to see the other options.

Yep, that's correct, as long as there aren't any other 2008 domain controllers in the domain.

how would i check to see the new features that come with the 2008 functional level?

A list of the features available at each functional level is available from Microsoft here.

thank you guys for your help