Hi,
I currently run nsd3 on 2 128MB VPS for my own domains and I have a script that rsyncs the 2 VPS when I make changes to one of them. The uptime on my ns1 is great (370 days) and recently the provider had to take it down for maintenance for couple of hours. It was at that time I noticed my ns2 isn't picking up because when I tried to go to any of the domains addresses, Chrome would say name could not be resolved.
Can anybody suggest some things I can look into to see why traffic isn't going to ns2 when ns1 is down? I did register both ns1 and ns2 IPs in my domain registry.