Optimizing worker_processes, worker_connections & PHP_FCGI_CHILDREN - Any Good Tutorial?

[Rahul Bansal]

> the FCGI_OVERLOADED (according to fcgi spec) feature..  to let the webserver
> know sooner that there aren't enough resources on the backend to process the
> request rather than after timeouts

My purpose of starting this thread is the same as FCGI_OVERLOADED.
I want to tweak my server before it gets overloaded.
Thanks to nginx, I haven't faced any downtime in months. :)
(Apart from one in a while timeout alerts I get form uptime monitoring sites)