[Samba] Failover DC did not work when Main DC failed

[Paul Littlefield]

We have a main DC (dc3) and failover DC (dc4) running in a Proxmox virtual environment.

Both DCs are replicating happily and have been running for over a year with no problems.

This morning, our main DC (running as a VM) was backed up and then restarted but Ubuntu did not start the 'samba-ad-dc' service on boot.

The failover DC was up and running at the time, but staff could not log in on their workstations and the QNAP file server (which is domain joined) was also not happy.

The fix was to reboot and everything was well again.

Lesson learned... check port 135 as well as port 22 on Nagios, and check that the failover DC works!

My question... why didn't the failover DC do its job?

Thanks,

Paul