I've been running http://tracksruns.com (source http://goods.tracksruns.com/runs.arc.txt) behind apache on ubuntu with mzscheme 360. It gets virtually no traffic but has been up without problems since I started it a month or so ago. I launched it using screen so I can get back to the REPL whenever I want. The server uses some globals that are interesting to look at like optimes*.
It's still on arc0. The main gotcha is that it thinks all requests are from 127.0.0.1 because it does not pay attention to apaches's X-Forwarded-For header.
Thanks - I had forgotten about the repl operator that pg mentioned in that thread. I'll have to try that out.
I love the quote from Ron Garret about the benefits of a REPL.
"Debugging a program running on a $100M piece of hardware
that is 100 million miles away is an interesting experience. Having a
read-eval-print loop running on the spacecraft proved invaluable in
finding and fixing the problem."
I got it to work behind apache with mod_proxy. One gotcha I never got around to fixing was getting the arc app to pay attention to the X-Forwarded-For header instead of just using 127.0.0.1 as the remote ip address.