> I'm fairly certain that the higher-ups in Twitter weren't told "We have pretty good failover protection, but there is a small risk of catastrophic failure where everything will go completely down." Whoever was in charge of disaster recovery obviously didn't really understand the risk.

Is this really a valid conclusion to come to at this point? I expect downtime in any service I operate. It's just how the world works. Does that mean I don't understand the risks and am misleading the board?