consider that running a complex piece of software on o&o hardware is very different than amazon. You have to re-architect your app to tolerate (1) hardware jus

consider that running a complex piece of software on o&o hardware is very different than amazon. You have to re-architect your app to tolerate (1) hardware just disappearing (yes that happens in a data center but much less often than in amazon), (2) generally lower-powered hardware (no giant db servers running on TB+ ram / fusion-io drives / bonded 1g ethernet hardware), (3) often shitty network and ebs performance, (4) generally a very different HA architecture. Not to mention ops relearning everything they know about how to keep your site up.