AWS Global Infrastructure: Availability Zones
An AWS Region (with the current exception of the Osaka-Local region) encompasses at least two distinct Availability Zones connected to each other with low-latency network links. Although, for security reasons, Amazon zealously guards the street addresses of its data centers, we do know that a single AZ is made up of at least one fully independent data center that’s built on hardware and power resources used by no other AZ.
As shown in Figure 4.2, AWS resources based in a single region can be requested and run within any AZ in the region.
FIGURE 4.2 A representation of AWS infrastructure divided among multiple regions and Availability Zones
The advantage of this level of separation is that if one AZ loses power or suffers some kind of catastrophic outage, the chances of it spreading to a second AZ in the region are minimal. You can assume that no two AZs will ever share resources from a single physical data center.
