phranque - 10:21 am on Oct 30, 2012 (gmt 0)
Registrar -> DNS server -> Hosting Company
I never put all 3 in the same location, ever.
this is the most important snippet from this entire thread.
within that i would add one more extremely important bit of redundancy and that is to insure that your DNS configuration specifies at least two completely autonomous systems - different subnets, organizations and locations.
next, regarding your timer settings on the SOA records:
make sure the Refresh time is short enough to match your maximum allowable downtime.
8 hours is an optimal number for efficiency reasons on a good day, but when the news is all about the weather you might want to temporarily bump that down to an hour or two in advance of a possible disaster.
likewise the Expire number should be long enough to ride out a bad connection to or temporary problem with a primary server.
7 days is typically a good number here.