Our advanced automated monitoring system runs 24x7 to keep an eye on all of our servers.  It queries our servers and major services every few minutes, and also executes certain web pages to ensure no application services are down. If it does discover a problem, it tries to rectify the situation automatically and if it can't, it notifies us by e-mail and pager so we can respond quickly to resolve the issue and keep downtime to a minimum.

We also have a sophisticated system that determines when any of our physical servers fail and automatically restarts the failed server on another physical machine. This way even if we have a hardware failure, your site will continue to operate!