Used in conjunction, NginX and Node.JS are the perfect partnership for high-throughput web applications. They’re both built using event-driven design principles and are able to scale to levels far beyond the classic C10K limitations afflicting standard web servers such as Apache. Out-of-the-box configuration will get you pretty far, but when you need to start serving upwards of thousands of requests per second on commodity hardware, there’s some extra tweaking you must perform to squeeze every ounce of performance out of your servers.
Video: http://joyent.com/blog/linux-performance-analysis-and-tools-brendan-gregg-s-talk-at-scale-11x ; This talk for SCaLE11x covers system performance analysis methodologies and the Linux tools to support them, so that you can get the most out of your systems and solve performance issues quickly. This includes a wide variety of tools, including basics like top(1), advanced tools like perf, and new tools like the DTrace for Linux prototypes.