Bring up your DC1 and it will update the DC2 snapshots.
after a period of having one or both servers off replication will cease to happen
change the following REG Key on all servers
Allow Replication With Divergent and Corrupt Partner click modify and change the 0 to a 1
change the registry key again
and it should continue to replicate
we had this on some of our 2008 servers after easter and the summer breaks as servers havent comunicated with each other in a cupple of days they need to be forced to accept the changes from one of the other DC'S. the servers tumbstone replication if turned off to prevent errors from relicating over all of the DC'S
there is a command to run to do this but i cant remeber what it was, or find it but the reg key does the same thing
As for the DC issue - do you not have a full backup?
Yes, a bare metal backup to a USB drive on the main DC.
Ok I've been away for a few days and left the network limping along (although not causing massive problems just yet). My plan was to recover DC 2 from a backup, however i noticed that, despite DC1 being a GC and owning all of the FSMO roles, when DC2 goes down, so does exchange!. So i need to figure out how to ensure that DC1 is being picked up as the GC on Exchange to ensure it stays working.
Also when I look at ADSI it shows the following USN No's
when connected to D1
DC1 current = 3296774
DC1 original = 13488
When connected to DC2
DC1 current = 3556594
DC1 original= 215976
DC2 current= 3664622
DC2 original= 13418
Although DC2 is supposed to be the usn rollbacked DC, it is showing a higher USN. Should I be using this one to replicate from? and instead of demoting and promoting DC2, I should actually be carrying out this task on DC1?
The deeper i get the more confusing this seems.
Thanks for all of the info and help so far.
many thanks and merry Christmas!
Which version of Exch?
It's Exchange 2007!
Sorry if I've missed something but I kinda just scanned the previous posts. From what I can tell, you're saying DC1 has an upto date copy of the database?
Can you not just do a dcpromo /forceremoval on DC2. Do a metadata cleanup from DC1, then manually delete DC 2 from DC ADUC.
You should then be able to add DC2 back to the domain and repromote it - forcing it to pull through a fresh copy of AD.
The only consideration you now need is your Exchange issue. Without knowing your setup I'm not sure why it's only reliant on this DC. Do you DC's current sit within different sites in sites and services? If so is the subnet for exchange added to the DC2 site? It should automatically look for another GC if DC2 fails, but I can't think of any other place you nominate 1 individual DC.