# What Are Regions and AZs?

#### Regions and AZs

A region and availability zone (AZ) identify the location of a data center. You can create resources in a specific region and AZ.

- A region is a physical data center. Each region is completely independent, and thereby improves fault tolerance and stability. After a resource is created, its region cannot be changed.
- An AZ is a physical location using independent power supplies and networks. Faults in an AZ do not affect other AZs. A region can contain multiple AZs that are physically isolated but networked together. This enables low-cost and low-latency network connections.

Figure 1 shows the relationship between regions and AZs.
Figure 1 Regions and AZs

#### Region Selection

You are advised to select a region close to you or your target users. This reduces network latency and improves the access success rate.

#### AZ Selection

When determining whether to deploy resources in the same AZ, consider your application's requirements for disaster recovery (DR) and network latency.

- To prioritize DR capabilities, deploy resources in different AZs in the same region.
- To prioritize network latency, deploy resources in the same AZ.

#### Regions and Endpoints

Before using an API to call resources, you will need to specify the resource region and endpoint. For details about public cloud regions and endpoints, see Regions and Endpoints.

Parent topic: FAQs