Comment by xp84
5 hours ago
Yup. I don't know enough people at giant companies to know how many actually do this though. Not just talking having 2 AZs, I'm talking about ability in a DR scenario to fail over, within 5-10 minutes, to a different cloud provider, e.g. AWS → Hetzner, or GCP → Azure.
My gut feeling is that the number of significant applications that have this capability can probably be counted on two hands. Especially since a lot of the largest footprints of software stacks running in the cloud belong to Google and Microsoft, who I'm pretty sure do not replicate their services into someone else's cloud.
Before the cloud it was commonplace to have redundant data centres from two or more colocation provider companies. Similarly, Internet uplink diversity was commonplace.