Hacker News Reader

Comment by gm-conspiracy | Hacker News Reader

I thought AZs were in the same physical location, just separate networks, no?

They are separate datacenters, I don't think they make any promises about how far they are apart from each other, but at least in some regions they are 10+ miles apart.

The AWS Cloud infrastructure is built around AWS Regions and Availability Zones. An AWS Region is a physical location in the world where we have multiple Availability Zones. Availability Zones consist of one or more discrete data centers, each with redundant power, networking, and connectivity, housed in separate facilities

https://docs.aws.amazon.com/aws-technical-content/latest/aws...

So, a single AZ could span across multiple physical locations, as well?

Am I reading that correctly?

Others have answered, but I think the general principle for a Region is that between the AZs you have less than 1ms latency, physical separation between the data centers, but they may still be in the same floodplain, be able to be hit by the same hurricane, etc.

More info here if you want to see how regions are structured at a high level of detail: https://youtu.be/AyOAjFNPAbA?t=15m21s

Nope. They aren’t even in the same city. For example, each of the AZs in us-west-2 are separated by about 50-60 miles.

This doesn’t list all the locations, but is a good map to get an idea:

https://www.google.com/maps/d/u/0/viewer?ll=50.9584270000000...

That map is incorrect: us-west-2a, 2b and 2c are not static names for the AZs. Every user gets their own mapping of which physical location is a, which one is b and which one is c. My us-west-2a may be your us-west-2c. They are not the same.

Extremely interesting, thanks for this clarification. For those curious, it's documented here[0] -- search for "To ensure that resources are distributed across the Availability Zones for a region"...

[0] https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-re...

Yes, I know they pseudo randomize the allocations. That is irrelevant to my core point, that each AZ is not just separate networks in the same building or even adjacent buildings, but rather they are truly isolated by a non-insignificant distance of somewhere around 50mi on average.

It's a cool map, but I can't find any reference for the source of the data center locations.

AWS purposely doesn't publish that information, and while I can believe it's possible to crowdsource the data by doing a little sleuthing (or working for certain vendors), it's hard to trust the map without knowing the sources.

There’s a The Atlantic article[0] that explains how to source the data pretty easily if you are willing to put in the effort.

https://www.theatlantic.com/technology/archive/2016/01/amazo...

No, they're different physical locations.

From https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Conce...:

> Each AWS Region has multiple, isolated locations known as Availability Zones.

And from https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-re...:

> Each region is completely independent. Each Availability Zone is isolated, but the Availability Zones in a region are connected through low-latency links.

Reply on news.ycombinator.com