[ Thanks to Lee Schlesinger for this link. ]
Rather than give up Apache, you can speed up your current HTTP
server while keeping your current setup (almost) intact by
installing a reverse proxy server in front of it. A reverse proxy
fetches resources from one or more servers and returns them to the
client as if they originated from the proxy server itself. Apache
can act as a reverse proxy with the mod_proxy module, but there is
no actual benefit to running mod_proxy on the same system the
Apache web server runs on, plus it consumes more system
resources.Therefore, for this setup, we will use an alternative web
server, nginx, which is lighter and more efficient. With this
approach you can have Apache serve all dynamic content and nginx
handle all static files without consuming lots of system resources,
combining the benefits of both servers without changing the whole
infrastructure.