After I got it working and PHP configured to run persistently the load average on the server went up and up all the time. I couldn’t figure out what was wrong but the PHP processes were there right at the top of the output of top.

When I went back to Apache things got back to normal. It wasn’t that the Supercache files weren’t being used or whatever because when I went back to Apache that was serving content directly for a bit while I got the mod_rewrite rules in there.