No one wins an award for having the most popular status site. I'll show you the top practical techniques we (37signals) use for keeping our sites available at all times, even during scheduled maintenance! From hardware choices, to network topology, to high availability services, it all matters. I'll introduce tools like intermission and mysql_role_swap and show you how we've used custom alerts and dashboards built on top of statsd + nagios to intercept problems before they impact users.