If you need to turn off the main DC while leaving the additional DC on, what pitfalls can wait?

Question

Active Directory

2 DCs in the network (DNS on both), the main one with all roles must be turned off for prevention. Both are registered on WS in a network as DNS. What pitfalls await or what action should be taken, or can you just turn off the primary controller?

Answer 1

If temporarily, then none.
Sometimes there are problems in the DNS, clients stubbornly refuse to go to the secondary.
There may also be problems with the exact time on a rebooted server, especially in a virtual environment.

Answer 2

Transfer FSMO roles from DC being switched off...

Answer 3

first serve the second, then transfer the roles to it and do what you want with the first. what is the problem?