Backup DNS servers? They fail as well once the zone is expired….

Recently I set up backup DNS-servers, with keeping in mind that I will have some faill-over once the primary DNS-server fails :-P

So I had configure and as secondary DNS-servers for several domains and the as primary DNS-server. Yesterday I had some issues, because none of the systems was reachable using their FQDN. First I restart the nameserver on and found somehow that the zone-files were expired :-( After some further investigation I found that the DNS-server on morpheus died somehow, so tank couldn't check for updates.

So the lesson learned of the above is... Even if you have backup DNS-configured... they will only serve for the period mentioned in the expiry field of that zone. :-|