[Building Sakai] More tomcats or bigger tomcats?

[Joshua Swink]

Is it better to run more tomcat instances, sticking with the default 2
GB heap size, or to run a single tomcat per CPU, using as much memory
as can be allocated to each one?

We currently run four tomcat instances on two machines, load balanced
through Apache. Each one has the recommended 2 GB heap size.

Our user load is always on the increase, and I was wondering what is
the better configuration:

- Increase the heap size on each tomcat's JVM? Perhaps to 3 GB.
- Leave the heap size at 2 GB and run additional tomcat instances.

Our current servers have 16 GB memory, so that works out to about 4-5
tomcats per machine if we stay at 2 GB heap per instance. My main
question is whether people have experienced better performance using
more 2 GB tomcats, or fewer tomcats with larger heap sizes.

Also, our servers have 2 CPUs each.

Thanks for any advice!

--
Joshua Swink