[photon]

So I take it to mean that a total reset involves a new IP address from BlueHost (meaning you'd have to change the DNS records for the domain to point to the new server), while a reimaging means you're essentially keeping the same server and they'll just wipe it and reload the bare OS on it?

Is it possible for them to bring up a new server, then you could set it up as necessary, then they could just switch the IPs so the new server has the IP of the old server? Probably not as they probably don't have that kind of functionality in their system but is worth asking.

I guess the question is how much downtime is tolerable.. Does the website content change due to user input? I.e. in an ideal world if you had DNS control, would you still need downtime to migrate a database or set of files over (disable the production site, move the critical files over, then point the DNS at the new server and wait until the DNS change migrates)?

If some downtime is tolerable, then you can minimize it by scripting or automating as much as possible.. start with a blank install of CentOS in a VM and then do everything you need to do to get it running.. make copies of config files so you can copy them into place, create a shell script to run all the commands, etc. Still downtime, but minimizing it.