So, Amazon has said since the introduction of EC2 that, to ensure really high uptimes, customers should use multiple availability zones and architect their applications to survive an outage in a single availability zone. While I would question Amazon's competence if outages of any sort were overly frequent, Amazon has not had many at all and no recent cross-AZ ones. [This is correct, right?] I recognize that architecting applications to be performant across datacenters (tolerant of relatively high-latency replication), but Amazon seems to be a poster child for keeping its promises w.r.t. availability. Is my take on this incorrect?