I have a network with one domain controller and 2 NAS-servers (running on a built-in Linux OS). Permissions to the files on the NAS servers are handled through AD rights. I want to bring the DC down for a short while (up to half an hour) and need to know if people who already are accessing the NAS-servers are still able to do that while the DC is down (as long as they don't logoff, reboot etc their machines).
As long as the NAS is using Kerberos, you should probably be fine. You can use
That said, only having 1 DC is dangerous. You should always have a minimum of two. In addition to mitigating the danger of a failure, it also would make situations like this go away.