So basically, we're currently testing out our new 2012 forest/domain and setup 3 2012 DCs. Everything worked well and we were starting to get ready to go into production state soon. Luckily for us, there was a power outage and after that one DC crashed and Windows refuses to start and we've been trying all kind of things these past days to get it to work with no success. Anyway, that's besides the point but just some background information.
The server that crashed is our "primary" DC, or the DC we setup first and installed the forest/domain on. The other two were joined.
We thought with two backup DCs it wouldn't be a problem if one crashed, but apparently it was a huge problem. The other two DCs now cannot connect to the forest/domain, cannot replicate, cannot do anything. Were these DCs just fetching data from our primary DC all the time and basically serving as load balancers?
It's not a huge problem to redo everything (very annoying though) and since we hadn't yet reached the production state we didn't have backups. Although, the data so to speak is still safe on the disks, it's just Windows that cannot start due to winlogon.exe/csrss.exe problem.
So basically my question is: Why does all DCs fail if our "primary" DC fail?