Emergency backup for a small net

Kent W. England wrote at NANOG:

And I would have the web servers addressed with overlays, using DNS to
switch between ISP addresses.

However, even if you manage to dynamically switch addresses at your name
server, folks would still have the cached values. I believe Paul Vixie has
described this technique earlier: run Squid in accelerator mode so that
you have an automatic mirror site. If the link to the original one
gets cut the client ought to try the next one (however I think the
common clients retry only when they get Connection Refused?)

Even with HTTP 1.1, caches and mirrors are good performance enhancements
because no one point is close to every other point on the Net.

Yup. That's why I wish the big providers would run caches that their
overseas customers can parent against. While the NLANR services are
great, they are free, and I for one would be more comfortable if it
were paid for and had a service guarantee.