Why bother with Squid as a purely proxy server? Isn’t most of the content on the Internet today dynamic?
Perhaps; perhaps not. A few years ago “media caching” required licenced software to handle WMA and RealMedia streams; today the heavy bandwidth users are flash videos from popular sites such as YouTube. The HTML may not be cachable but all those thumbnail images, all those previews and all those large flash video files are very cachable. The problem isn’t that the Internet is “dynamic”; the problem is that website designers view caching as “evil” – they’re suddenly not 100% in control of their content – and try as hard as possible to dodge caching.
Squid has a few knobs which can be set to cache this so-called “dynamic” content. Squid has to treat everything which may be dynamic as uncacheable – the telltail “?” in the URL identifying the output as being from a script – when in fact the content isn’t all that dynamic. More on that will be covered in a future article.
ISPs who run Squid with a well-tuned configuration have shown web traffic savings of around 30%. Thats 30% of their traffic, not just hits. And thats not with any attempt at caching the “dynamic” content which can actually be cached – Youtube and Windows Updates are two big offenders here.
So Squid isn’t that useless at all!
A couple of articles which give an overview of caching follow. They’re dated – the technology isn’t new after all – and just as applicable today.
- ComputerWorld (Traditional forward proxy/caching) – QuickStudy: Web Caching
- Tech Republic (Application Acceleration) – 8 Simple Caching Rules: Web Caching Your Application For Fast Response Time