Ok, I've been playing with EC2 and S3. Using quite a long and complicated script to create an AMI (which is Amazon's term for a disk image). The script is coming along nicely, using debootstrap to create a Debian etch image.
Yesterday and today (well, only in the evening today), I've been trying to get MySQL working on an s3fs drive, but I'm afraid that's not going to work. Well, part of it might be because I'm trying to set it up from home and not from an EC2 instance, but still. MySQL just refuses to start with a weird message:
Starting MySQL database server: mysqld . . . . . . . . . . . . . . failed!
invoke-rc.d: initscript mysql, action "start" failed.
After which it hangs, altough it seems like MySQL did start. Maybe it's something with the initscript. I realised in the end that I don't really need MySQL running in such a setup. Making dumps every so often should be enough for what we have in mind. So I'm going to script an automatic recovery of the database, based on a dump every 5 minutes. That should work without losing any speed.