RoR Deployment

So.. I've been reading about RoR and deployment here and there. Basically it all comes down to running a mongrel for each cpu.

But what if you run 40 rails apps on a single box? will that result in 160 mongrels on a quad-core? And 40*50mb = 2GB of ram?

Isn't it possible to run multiple rails applications on a single mongrel?

Also, I'd like to know if there is some sort of tool that will manage mongrels accross all my servers, and deploy application to servers (and maybe do all that on EC2?) depending on the load / availability.


So far RoR is nice to me. But I haven't deployed it yet on a production environment. I'll be installing redmine on one of our servers. just to see how that will behave.