Nginx and Memcached

“If web architectures, performance, or scalability are topics you would like to keep on top of (who doesn’t!), then chances are, you’ve heard of Nginx (”engine x”). Originally developed by Igor Sysoev for (second largest Russian web-site), it is a high-performance HTTP server / reverse proxy known for its stability, performance, and ease of use. The great track record, a lot of great modules, and an active development community have rightfully earned it a steady uptick of users, and most recently, a notable mention in the Netcraft report.”

“Memcached, the darling of every web-developer, is capable of turning almost any application into a speed-demon. Benchmarking one of my own Rails applications resulted in ~850 req/s on commodity, non-optimized hardware – more than enough in the case of this application. However, what if we took Mongrel out of the equation? Nginx, by default, comes prepackaged with the Memcached module, which allows us to bypass the Mongrel servers and talk to Memcached directly. Same hardware, and a quick test later: ~3,550 req/s, or almost a 400% improvement! Not bad for a five minute tweak!”

“The only snag in our scheme for easy performance gains comes with the fact that more often than not, our application servers contain additional caching policies (read invalidations / authentication), and MIME type logic. The former, as recently documented by Tobias Lütke and Geoffrey Grosenbach, if properly thought through can be solved with some clever URL rewriting policies and automatic TTL timeouts. When implemented correctly, we could simply set the memcached key to be the full request URL, allowing us to completely bypass our app. servers.”