Link to home
Create AccountLog in
Avatar of johnnymac08

asked on

How do I reinstall a failed domain controller that is offline and being reloaded

We have 2 DC's in one domain, one dc failed and is offline. The other dc is functional and running. I need to remove the failed dc from the active server in active directory. I tried using the ntdsutil but since the failed server is offline i cant connect with it.
Avatar of martin_babarik
Flag of Czechia image

what do you need to transfer exactly? There are just few considerations:
Where do you have your FSMO roles? If they were on the failed DC, you can seize them using ntdsutil. If they are on the active DC, no need to transfer anything.

If all FSMO roles are on the running DC, just install Windows 2003 server on another computer, add this computer to domain and promote it to DC. Everything will replicate automatically.
Avatar of johnnymac08


I looked at the running server and followed Microsofts directions to determine FSMO roles and the running server has all roles assigned to it.

So you are saying that all I have to do is delete the failed server from AD users and computers and that will remove the failed server from AD along with all DNS entries? And add the reloaded server to the domain and promote it after adding to domain?

And then AD will replicate to the new server and I will have the 2 DC's that I had before?
Avatar of martin_babarik
Flag of Czechia image

Link to home
Create an account to see this answer
Signing up is free. No credit card required.
Create Account
Thanks for thhe fast feedback Martin.  Deleting DC from active directory gives me 3 choices.  

Restart AD Replication
DC Permanently offline

Which do I choose?  The offline server has already been reloaded and is ready to be added to AD.

I see - so you fixed the failed DC? If so, I'd choose Restart AD replication.
No, we reloaded it, due to a bad motherboard, and are ready to join it to Active Directory.  Thanks.  So is your answer still the same?
I see...well if it's on a replaced HW, it's clean installation and you are going to promote it under the same IP and hostname like the gone DC, I'd choose Demote first, then check if everything works so far, join the new one, check if joining the domain created the correct computer account (doesn't matter where at the moment), and if all is ok, promote it to DC.
It will not let use demote since it's offline.  Our only option is to delete, join the domain, then go through the active directory wizard.  Going through the AD Wizard, we get a window saying: "directory configuration info indicates that a DC  name our server already exists, do you want to continue?  If yes, all info on DC will be replaced.  Sound good to you?
More safe to me sounds the option that you will give the new server another name and join the domain under this name. It's not neccessary but seems to be less drastic and less painfull - if it's not in contrary with some of your company policies or something like that.
Alright Martin.  Everything went ok well we think.   However, in event viewer under directory service we are getting this warning:  Internal Event:  The following schema class has a superclass that is not valid.  We replicated AD from an Exchange server that has all FSMO roles.

Do you know how we can get rid of those warnings?  Should we  be worried?

Auuuu why you didn't mention you have an Exchange?:-))
Ok, not such a problem I guess. The AD should be working fine, but the replication is going in the right direction from the running DC to the new one, so I'm quite sure that the inconsistency will be aligned automatically as your original DC is the holder of the Schema master role.
The problem you are experiencing is because installing Exchange modifies the schema and ads more classes and attributes. The original DC already has them all, but the new one not yet. Give it some time and hopefully it will be fixed automatically.
We are no longer getting this: The following schema class has a superclass that is not valid.
Thanks Martin.
Thank you.  
You are welcome, I hope everything will work perfectly:-) Thanks for points.