Mostly security -- DNS is one of the worst offenders when it comes to protocols with security problems, both in terms of protocol issues and bugs in implementations.
Amazon doesn't move endpoints very often, and I round-robin requests to several endpoints; so in the rare cases an AWS endpoint changes I see a slight decrease in Tarsnap performance and can make the Tarsnap server stop using the dead endpoint before any users are likely to notice.
Amazon doesn't move endpoints very often, and I round-robin requests to several endpoints; so in the rare cases an AWS endpoint changes I see a slight decrease in Tarsnap performance and can make the Tarsnap server stop using the dead endpoint before any users are likely to notice.