Can you provide a citation to that level of geographic diversity per region? My understanding is that all AZs are within the same physical facility, but independent networking and power.
AWS has a map that shows the physical location of all data centers. us-west-2 for example is split up among three cities in Oregon. Probably 60-70mi between each of them.
An Availability Zone is represented by a region code followed by a letter identifier; for example, us-east-1a. To ensure that resources are distributed across the Availability Zones for a region, we independently map Availability Zones to identifiers for each account. For example, your Availability Zone us-east-1a might not be the same location as us-east-1a for another account. There's no way for you to coordinate Availability Zones between accounts.
The long and confusing explanation:
At least not in us-east-1 and us-west-1-2, but I am pretty sure many of the large regions are also run in multiple physical facilities.
The so-called availability zone is an abstract and virtual concept. Let us use us-east-1 as an example.
Assume the following:
* Physical DC buildings: Queens, Brooklyn, Manhattan, Staten Island
* AWS accounts: Joe, Alice, Bob
* AZ: us-east-1a, us-east-1b, us-east-1c, and us-east-1d
Every AWS account in us-east-1 region is assigned three AZs. But for sake of this explanation, we assume only two.
* Joe: 1a, 1b
* Alice: 1a, 1b
* Bob: 1a, 1c
You now ask, "WTF?" but you let this go, think this is done for capacity reason. So do we actually have four different physical facilities, one per each AZ? Nope.
So is 1a and 1b in the same facility? Not necessarily, but very possible.
So 1a and 1b in Queens, 1c in Brooklyn, and 1d in Manhattan? Nope.
So what the fuck is AZ? What is the relationship between AZ and physical facility?
Think about virtual memory address space.
Joe's 1a and Bob's 1a are in Queens, but Alice's 1a is in Manhattan. But Joe's 1a and Bob's 1a are on a different floor, different racks, while Joe's 1b and Bob's 1c are in Brooklyn and on the same floor. This is why certain customers run out m3.xlarge in 1a but others don't in their 1a.
In essence, AZ is a label and is unique per account. AZ is very similar how virtual memory address in OS looks like.
We learned this because our EMR failed due to low capacity in one account.
"Amazon initially said little about the physical layout of AZs, leaving some customers to whether they might be different data halls within the same facility. The company has since clarified that each availability zone resides in a different building."
“It’s a different data center,” said Hamilton. “We don’t want to run out of AZs, so we add data centers.”
To make this work, the Availability Zones need to be isolated from one another, but close enough for low-latency network connections. Amazon says its zones are typically 1 to 2 milliseconds apart, compared to the 70 milliseconds required to move traffic from New York to Los Angeles.
“We’ve decided to place AZs relatively close together,” said Vogels. “However, they need to be in a different flood zone and a different geographical area, connected to different power grids, to make sure they are truly isolated from one another.”
So, distance of availability zones from each other is limited by speed of light in fiber optics (which is slower than through a vacuum or microwave wireless).
Based on this calculator: http://wintelguy.com/wanlat.html, availability zones can't be more than 0.5-1 miles apart (about) to retain their 1-2 millisecond network latency, so they're different buildings in the same industrial/business park. We could confirm this by pulling permits (public record) in Amazon's (or their subcontractor's) name.
That is not a guarantee. AWS doesn't actually publish more than what I cited (well there are photos of the DC flooding around the Internet). But there are different physical facilities, and they are some miles apart. Like I said above, 1a for Joe and 1a for another customer don't have to be in the same building, or on the same floor.
Source: I emailed Jeff Barr and asked.