I also use Mongrel behind Apache, but I’ve heard good things about
nginx too. I would say you can expect your Rails/Radiant processes to
consume at least 20MB of memory, on average around 30-40, including
RMagick or ImageScience.
For reference, seancribbs.com is running behind Apache 2.2 on one
Mongrel and there’s another app on there that has two of its own.
This server is also running MySQL so it gets close to the 256MB limit
at times, but I’ve never had notice of an over-use (yet). If their
needs aren’t that intense, sqlite3 might be a good solution for the
I’ve also had great success with Litespeed; kckcc.edu uses that, with
its built-in Rails support. I’d say it consumes about as much as the
I second Daniel’s observation about ‘personal preference’, too. Really
it comes down to what you want to do and can put up with!