Need direction to Re create a domain controller

[jl3574]

I have a network with 2computers A and B that are responsible for domain controller ,dhcp and dns. i don't think it is setup probably cause if A goes down the whole network doesn't work and if B goes down the same. Where A is the primary and B is the backup.

What i want to do is dump A and B because they are slow and old i want to Re-create the DC with a New computer C.
my quesiton is what is the best procedure to do this?
delete the whole forest tree in A and B re-create it with C?
or create the forest first in C then remove B and C?

and because i have aplications running on the network at all times my down time is only a day.

 

[Davetoo]

Build the new computer C, DCPROMO it into the domain. Transfer all the FSMO roles to C as well as DNS and DHCP and make C a GC. DCPROMO A out, DCPROMO B out. Don't get rid of A and B until you're positive C is working properly and that you have no issues on your domain.

That's very simplified, but in a nutshell what you need to do to accomplish your goal.

I'd advise once C is up and running, bring another server into the mix, D, DCPROMO it, make it a GC as well and spread the load between those two.

You can do all of this with no downtime to your network at all if you do it the right way.

I'm Certifiable, not cert-ified.
It just means my answers are from experience, not a book.