DESIGN

unicornの設計方針。 / “File: DESIGN [Unicorn: Rack HTTP server for fast clients and Unix]”

Simplicity: Unicorn is a traditional UNIX prefork web server. No threads are used at all, this makes applications easier to debug and fix. When your application goes awry, a BOFH can just “kill -9” the runaway worker process without worrying about tearing all clients down, just one. Only UNIX-like systems supporting fork() and file descriptor inheritance are supported. The Ragel+C HTTP parser is taken from Mongrel. This is the only non-Ruby part and there are no plans to add any more non-Ruby components. All HTTP parsing and I/O is done much like Mongrel: 1. read/parse HTTP request headers in full 2. call Rack application 3. write HTTP response back to the client Like Mongrel, neither keepalive nor pipelining are supported. These aren’t needed since Unicorn is only designed to serve fast, low-latency clients directly. Do one thing, do it well; let nginx handle slow clients...

Full article: http://unicorn.bogomips.org/DESIGN.html