High traffic websites can be distributed to different servers, either to better spread out the workload or to achieve redundancy. Each server in the cluster of systems would have their own copy of the website or web application's files and be capable of satisfying the user's request. The trick then is to route the user's request to one of these servers in an orderly fashion. There are different approaches to this, but a common one is to set up a load balancer or reverse proxy server.

NGINX is somewhat newer to the scene than Apache; written a little over a decade ago specifically to handle high-load connections, it can function as a web server, proxy, cache, and load-balancer. In this recipe, we'll see how to set up NGINX as a load balancer to proxy requests between the client and a cluster of Apache servers.