If your website has decent volume and you are using mod_perl with lots of dynamic content (hopefully with templating), then you probably want to be using a reverse proxy setup.

Let me second (or third or fourth?) that thought.

I'm using a reverse proxy cache for stonehenge.com, and the flexibility it offers is amazing and amazingly practical.

I also helped a large university do that, and their response time during heavy load went from 30 seconds to 2.5 seconds on one particular critical application.

It's a useful technique, even if you have only one machine, because it's still a net win, especially if you ever deliver to clients on slow networks.

I wrote about setting up a split-server arrangement in one of my columns.