AWS, for comparison:
> AZs make partitioning applications for high availability easy. If an application is partitioned across AZs, companies are better isolated and protected from issues such as power outages, lightning strikes, tornadoes, earthquakes, and more. AZs are physically separated by a meaningful distance, many kilometers, from any other AZ, although all are within 100 km (60 miles) of each other.
europe-west9 is the only large Google datacenter in France afaik. Building more would cost lots more money, and it seems like the market isn't there for it. Workloads that require data locality in France are presumably suffering the most. And there are knock-on effects on other datacenters from losing an entire huge chunk of capacity like this.
If that’s true, what’s the fucking point of separating them at all?
Their descriptions[0] however promise zones have a "high degree of independence from one another in terms of physical and logical infrastructure". Just how well separated this physical zonal infrastructure was remains to be seen ...
[0] https://cloud.google.com/architecture/disaster-recovery#regi...
> Regions are independent geographic areas that consist of zones. Zones and regions are logical abstractions of underlying physical resources provided in one or more physical data centers. > (...) > A zone is a deployment area for Google Cloud resources within a region. Zones should be considered a single failure domain within a region. To deploy fault-tolerant applications with high availability and help protect against unexpected failures, deploy your applications across multiple zones in a region.
You should use "region" and "zone" as abstract concepts with shared properties like network topology, local peering, costs, and availability. AFAIK no cloud provider discusses (nor provides guarantees) against specific threats or correlated failures.
There is no guarantee that a given risk will not impact multiple zones, but this risk is lowered by the implementation of various safeguards (for example, rollouts are not happening in multiple regions at the same time).
Google doesn't say "put your VMs in more than one zone because you can be sure we won't have all zones in a region down at the same time", but rather "by putting your VMs in multiple zones in the same region, you can target better SLOs that the SLOs in one zone".
Note that it's different from the concept of "availability zone" of AWS which explicitly says that AZs are physically separated:
> AZs are physically separated by a meaningful distance, many kilometers, from any other AZ, although all are within 100 km (60 miles) of each other.
https://aws.amazon.com/about-aws/global-infrastructure/regio...
They are actually in the process of building 3 more buildings a ways down the road for more capacity.
