Parent domain crash,how to create domain from exising additional domain

[Aatish]

Dear Friends,
We have setup of domain & it's additional domain:
Unfortunately our main domain crashes out & we don't have any system state of that.
We have additional domain for that server?
Can possible to recover main domain from existing additional domain ?
Waiting for your response...
Regards
Aatish

[Rune J. Winje · Accepted solution]

If you mean that you have no functioning domain controlleres left in the parent domain AND no backups, then no.

With a minimum two domain controllers you can allow for one domain controller failing even without backup, assuming they were synchronized when one failed. It is then a simple matter to seize the FSMO roles over to the remaining domain controller.
http://support.microsoft.com/kb/255504


If the only (or all) domain controllers in a domain have crashed and you have no good backup, then you will have to make a new domain. If it is a parent domain or forest root domain this means of course also the sub-domains have to be made from scratch... (document existing user accounts, security settings, policies etc, demote, wait for parent domain to be operational, promote again to DC for a subdomain)

This is why it should always be minimum 2-3 domain controllers in a domain. Alternatively with only one domain controller in a domain you MUST have a good backup and it must be acceptable for the users to have downtime while recovering the domain controller(s).


Cheers,
Rune