A geographic grouping of availability zones that forms the real unit of cloud risk concentration, because few workloads ever cross its boundary.
A cloud region is a geographic grouping of availability zones with its own control plane, and it is where a customer deploys data and workloads by default. It is the real unit of risk concentration, because crossing a region boundary means duplicating data, accepting latency and often paying transfer charges, so the vast majority of workloads stay inside a single region while their owners believe they are geographically diversified. A legal constraint compounds this: data residency rules imposed by sector or national regulation forbid precisely the diversification that resilience would call for. The consequence for an insurer is that a region-wide loss is the most credible cloud accumulation scenario, ahead of a provider-wide global incident, which is more spectacular but rarer and repaired faster. Mapping a portfolio by region rather than by provider is therefore the first step in any honest measurement of the exposure.
On 25 April 2023, water ingress followed by a fire in a battery room took out the europe-west9-a zone of Google Cloud in Paris. The whole region stayed degraded for days and some services were only restored weeks later.
cloud region, région d'hébergement, périmètre régional cloud