Ah - sorry! I don't mean a legal contract, I mean more of a technical contract. e.g. "I won't pass a null pointer" style contract.
In fact, the first bit you quoted provides an even stricter technical contract than the one on the main EC2 page - it states some degree of natural disaster tolerance, heavily suggesting separate datacenters (not just different floors). Thanks for pointing that out.
Whatever the common point of failure turns out to be, it does seem to have been shared across AZs, in violation of their FAQ.
In fact, the first bit you quoted provides an even stricter technical contract than the one on the main EC2 page - it states some degree of natural disaster tolerance, heavily suggesting separate datacenters (not just different floors). Thanks for pointing that out.
Whatever the common point of failure turns out to be, it does seem to have been shared across AZs, in violation of their FAQ.