Best web server to host multiple low hit rails/sinatra apps

I’m a kinda newbie in hosting, maybe my questions sound silly, but I
couldn’t find answers by reading manuals or googling. Please help!

I need to host a lot of simple rails/sinatra/padrino applications of
different ruby versions each with 0…low hits per day. They belong to
different owners and should be well isolated from each other.

When an app is hit it should respond in reasonably short time, but I
expect several simultaneous visitors hit the same site to be a rare
case.

I’m going to create separate os user for each application. Surely I’d
like to put them as many per server as it’s possible. Thus I need to
choose the web server with the lowest memory footprint, which can run
applications on behalf of different users with different ruby versions
and gemsets.

I consider lighthttpd,webrick,nginx+passenger,thin,apache+passenger
I suppose the reliability of all choices is sufficient for such a job,
and while performance isn’t an issue, the memory consumption is.

I found many posts regarding performance issues, but most of them
discuss the performance tuning and issues. I couldn’t find a comparison
of web servers memory usage when idle.

So which one would you choose for that job?

Sub Z. wrote in post #1062003:

So which one would you choose for that job?

I generally find the best way to find a suitable solution is to get a
server and test out what you’re trying to do.

My Rails apps are hosted on a MediaTemple (ve) server. More info at:
http://mediatemple.net/webhosting/ve/

Benefits are root access, relatively low monthly fee for what you get,
choice of OS, ease of reinstalling/switching OS’s, and you can add
additional resources as needed. For example, my (ve) server was running
low on RAM so I added another 512MB of RAM to my setup via the control
panel and instantly it was available for the OS to consume. But, as with
most servers, you’ll need to know how to setup Rails, Ruby, Apache,
Passenger, etc. on your own.

Another thing you could try is an Amazon EC2 Micro Instance. You can get
a free EC2 instance, throw Ubuntu on it, point your domain(s) at it, and
just like the MediaTemple (ve) server: configure it as needed. Info:
Compute – Amazon EC2 Instance Types – AWS (read about Micro)

In both cases you’d be able to host multiple users on each server and
can modify site directories via apache. Fairly straightforward as far as
I’m concerned.