Based on that thread it sounds like only AWS guarantees that their AZs are in physically separate DCs, while for Google and Microsoft AZs could be in separate buildings of the same DC facility.
Other cloud providers mostly just vaguely put things in another part of the building and say it’s “a separate AZ” but as GCPs woes highlighted that’s corner cutting that bites badly when the whole building has a problem.
In many cases in AWS an availability zone is actually composed of multiple datacenters, each with their own redundancies. This may not be true for smaller regions, but in large ones it definitely is. In those cases, losing an entire datacenter would maybe take out a percentage of instances in that AZ. This has happened before and our production systems barely noticed other than provisioning new nodes to replace the failed health checks.
I think you misunderstand Google's infrastructure. I'm guessing that each GCP zone is actually a Borg Cell (see: https://storage.googleapis.com/pub-tools-public-publication-... ). Borg cells tend to be isolated from eachother in many ways in the physical layer (networking and management being a big one, not sure about power). So networking or machine management for an entire zone could go down and not affect other cells. Changes also tend to get pushed on a per-cell basis when they are Google wide rollouts.
I believe GCP recommends to replicate data cross regions (https://cloud.google.com/architecture/framework/reliability/...).
Also see: https://cloud.google.com/architecture/disaster-recovery#regi...
Obviously every cloud vendor recommends replicating data between multiple regions, but fact of the matter is that a lot of cloud services work much easier with redundancy within a single region than multi-region redundancy.
I think Google designs their datacenters for their own needs and expect you (a product running in their DCs) to distribute by region. Almost products at Google will be operating in multiple regions given the reach of most of our services, so DC design followed that need.
Based on GCP's docs, they still think region separate is better. Not sure why you wouldn't just do that?
If there is a catastrophic event (a large tornado hit AWS us-east-2), those buildings are pretty close to one another and both likely would be taken out, right? So you could lose multiple AZs since they are physically located so close to one another?
It's incredibly rare for multiple AZs to go down at once, especially since they are more than a few miles apart from each other.
> Each Availability Zone is separated by a meaningful physical distance from other zones to avoid correlated failure scenarios due to environmental hazards like fires, floods, and tornadoes.
https://docs.aws.amazon.com/wellarchitected/latest/reliabili...
Very much so - Australia only got a second region this year, so if your work required data to remain in Australia, you just had to hope that ap-southeast-2 didn't have a major issues. I'm sure there are plenty of other countries with only a single region.
If I have to think too hard and do too much work about how I lay applications out, I might as well just rent in a colo.
It says "reserved for future use" but other docs mentioned "physical zone separation": https://googleapis.dev/java/google-api-services-compute/alph...
[edit: at least in regions where Google HAS its own datacenters, e.g. "us-central-1? yes. europe-west9? maybe not"].
That does not imply that Search / Drive / Gmail runs on top of Google Cloud.
Instead aim for uptime in a few regions, and load balance your users to regions that are healthy.
That design is far cheaper for both google and for you - and, in the typical case, users still get nice low latency to a local datacenter, and only in the rare failure case might they have to wait for latency to some other region.
Like, Target does not compete with Amazon. They have a totally different home delivery model that is not in the same category of reliability or service.
It's annoying.
No random online eshop can offer next day delivery across half the world unless they already have a logistics chain of 100,000 truck drivers spread across the world. But Amazon can.
Likewise, no cloud provider has enough data centers to offer multiple separate data centers in the same city, for hundreds of cities around the world. But Amazon does.
Any competitor can't offer amazons level of service until they get to amazon scale... Which they never will.