Which role must be available for users to logon ?
My answer would be PDC however in my lab which has two DC's which both have the global catalog I've moved RID, PDC and Infrastructure roles onto DC1 then powered it off but I'm still able to login on my test PC with two different accounts which are logging in via DC2.
This was a question I saw in a recent exam so I'm just wanting to verify my answer and my lab isn't helping !
Edit. this article seems to confirm it is the PDC, I should've googled a bit more before posting
Responding to operations master failures: Active Directory