Okay I lied, eAccelerator gives a pretty darn high ROI, but setting up a proxy cache gives a comparable or higher ROI. I chose to use Varnish as my proxy cache.
There were many confusing instructions on the web about how to configure Varnish. Here are the steps I took to setting up Varnish for a signal machine running both Varnish and the web server:
1) Port install Varnish.
cd /usr/ports/www/varnish/; make install clean
2) Change Apache’s port to 8080 by modifying this line in /usr/local/etc/apache/httpd.conf
3) Restart Apache
4) Start the Varnish daemon. Substitute the IP below with your machine’s internal network IP address. If you are hosting at home, it is most likely 192.168.0.* but you can run ifconfig to find out what it is.
varnishd -a <your-machines-internal-ip-address>:80 -b localhost:8080
That’s it! From now, all requests on port 80 should now be routed through the Varnish proxy cache. A proxy cache miss will seemlessly make Apache calls to serve the internet user without the user ever knowing it! A proxy cache hit would not access Apache (and therefore not access MySQL) lessening your machine CPU usage and increasing the speed & efficiency of serving objects to user.