alt Hacker NewsYou don't have to obey TTL. You can use Unbound options like:
cache-min-ttl: 3600 // seconds
cache-min-negative-ttl: 3600 // seconds
serve-expired: yes
serve-expired-client-timeout: 20 // milliseconds to wait for resolution before serving the old value to the client
Can also have unbound preemptively refresh cached values too...
Tada, now your unbound serves records faster than the round trip out to anything off your own network in most cases.