Using SQUID in a reverse-proxy mode
PHP/Mysql websites are great for easy and fast content development. But they are also resource hogs. What happens when your dynamic website becomes REALLY popular? Well, in a word, your website will grind to a halt (along with all the other domains hosted on the same machine!) What to do? Lot's of stuff -- you can try increasing MySQL's internal cache size, you can try to cache PHP output, etc. But when that is still not enough, you have to think bigger, and that's where Squid comes in. Here are two great articles on a real-life Squid reverse-proxy application:
Building an Edge Server With Squid 2.6 High-load Website (WordPress) Optimization : IlmuKomputer.com