Re: latency - be careful how you're testing. Providers often announce only a subset of their IP space from any given datacenter, so you might end up with eg. a

Re: latency - be careful how you're testing. Providers often announce only a subset of their IP space from any given datacenter, so you might end up with eg. a nameserver in Virginia, Dallas, and NY. If you run a synthetic round robin test you'll get variable latency. But actual resolvers will hone in on and prefer the fastest from the set, only occasionally checking the others; your real customer latency is generally equal to the fastest of available NSs. This plus the amount of caching that happens in DNS makes the performance implications of the design minimal, and it comes with huge availability advantages. That being said, you may still get crap latencies if all four of your NSs are getting anycasted to far away places. ;) I wouldn't read too much into amazon.com not being on R53. That company behaves like a diverse set of companies under one umbrella name, and some of those move at a much slower, much more conservative pace than others (more like "if it ain't broke...")