performance tuning

First off, Apache, nginx, or LightSpeed aside - if you're running a server with 1000-2000 requests/second it's time to start thinking about dual servers and load balancing. Depending on what you're serving you can easily get more out of any of those servers, but at those rates you're serving something important (or at least high-traffic), so you want redundancy in addition to the ability to handle momentary load spikes. Start seriously considering a load balancing infrastructure i.e. HAProxy and NGINX. You can certainly consider other high-performance web servers (nginx is very popular), or you can consider tuning your Apache configuration for better…