That's why I asked if that 99.999999999% durability number includes datacenter loss. It's an unlikely failure mode but is it .00000000001% unlikely? I don't kno

That's why I asked if that 99.999999999% durability number includes datacenter loss. It's an unlikely failure mode but is it .00000000001% unlikely? I don't know. Given the fact that Azure lost a datacenter with this failure mode, I don't think it's in the "likelihood of an asteroid destroying Earth within a million years" ballpark. Their durability page doesn't really clear it up, they say "Because at these probability levels, it’s far more likely that ... Earthquakes / floods / pests / or other events" known as “Acts of God” destroy multiple data centers". But from the post above: "any one file (or piece of file) is in exactly one datacenter." So it doesn't take multiple datacenter failures to lose data, just one unless you explicitly copy your data to multiple datacenters.