Infrastructure, like data centers and networking connectivity, still exists as the foundation of every cloud application. In AWS, this physical infrastructure makes up the AWS Global Infrastructure, in the form of Regions and Availability Zones.
Regions
Regions are geographic locations worldwide where AWS hosts its data centers. AWS Regions are named after the location where they reside. For example, in the United States, the Region in Northern Virginia is called the Northern Virginia Region, and the Region in Oregon is called the Oregon Region. AWS has Regions in Asia Pacific, Canada, Europe, the Middle East, and South America, and we continue to expand to meet our customers' needs.
Each AWS Region is associated with a geographical name and a Region code.
Here are examples of Region codes:
- us-east-1: The first Region created in the eastern US area. The geographical name for this Region is N. Virginia.
- ap-northeast-1: The first Region created in the northeast Asia Pacific area. The geographical name for this Region is Tokyo.
AWS
Regions are independent from one another. Data is not replicated from
one Region to another, without explicit customer consent and
authorization.
Availability Zones
Inside
every Region is a cluster of Availability Zones (AZs). An AZ consists
of one or more data centers with redundant power, networking, and
connectivity. These data centers operate in discrete facilities in
undisclosed locations. They are connected using redundant high-speed and
low-latency links.
AZs also have a code name. Since they are
located inside Regions, they can be addressed by appending a letter to
the end of the Region code name. For example:
- us-east-1a: An AZ in us-east-1 (N. Virginia Region)
- sa-east-1b: An AZ in sa-east-1 (São Paulo Region)
Therefore, if you see that a resource exists in us-east-1c, you can infer that the resource is located in AZ c of the us-east-1 Region.
Scope AWS services
Depending
on the AWS service you use, your resources are either deployed at the
AZ, Region, or Global level. Each service is different, so you must
understand how the scope of a service might affect your application
architecture.
When you operate a Region-scoped service, you only
need to select the Region you want to use. If you are not asked to
specify an individual AZ to deploy the service in, this is an indicator
that the service operates on a Region-scope level. For Region-scoped
services, AWS automatically performs actions to increase data durability
and availability.
On the other hand, some services ask you to
specify an AZ. With these services, you are often responsible for
increasing the data durability and high availability of these resources.
Maintain resiliency
To
keep your application available, you must maintain high availability
and resiliency. A well-known best practice for cloud architecture is to
use Region-scoped, managed services. These services come with
availability and resiliency built in. When that is not possible, make
sure your workload is replicated across multiple AZs. At a minimum, you
should use two AZs. That way, if an AZ fails, your application will have
infrastructure up and running in a second AZ to take over the traffic.
Source- Amazon