One of the phrases you hear associated with cloud computing is «architecting for failure.» Rather than build in a lot of hardware-level redundancy – power, disk, network, etc… – the idea is that you expect it to fail and can simply replace the application (which is what you care about anyway, right?) with a clone running on the same cheap hardware somewhere else in the data center.
Awesome idea, right?
But when it comes down to it, cloud computing environments are architected for scale, not fail.