I have a nice reliable (underused) server at Rackspace. I offered to host a site there for someone, because it's a site I use a lot, and it tends to go down regularly (bad hosting). It's a PHP/MySQL site, and he'd rather that I mirror it rather than just host it. Sounds fine to me, but how do you go about setting that up? Also, is there a way to make his DNS point to my server if his goes down?