Regions and AZs

Concepts

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

• Regions are defined by their geographical location and network latency. Public services, such as Elastic Cloud Server (ECS), Elastic Volume Service (EVS), Object Storage Service (OBS), Virtual Private Cloud (VPC), Elastic IP (EIP), and Image Management Service (IMS), are shared within the same region. Regions are classified as universal regions and dedicated regions. A universal region provides universal cloud services for common tenants. A dedicated region provides only services of the same type or provides services only for specific tenants.
• An AZ contains one or multiple physical data centers. Each AZ has independent cooling, fire extinguishing, moisture-proof, and electrical facilities. Within an AZ, computing, network, storage, and other resources are logically divided into multiple clusters. AZs within a region are interconnected using high-speed optical fibers so you can build cross-AZ high-availability systems.

Selecting a Region

When selecting a region, consider the following factors:

• Location

  Select the region closest to you or your target users to reduce likelihood of latency issues. Chinese mainland regions provide basically the same infrastructure, BGP network quality, as well as operations and configurations on resources. If you or your target users are in the Chinese mainland, it is not necessary to consider network latency differences when selecting a region.

• Resource price

  Resource prices may vary by region. For details, see Product Pricing Details.

Selecting an AZ

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

• For high DR capability, deploy resources in different AZs in the same region.
• For low network latency, deploy resources in the same AZ.

Selecting a Region and Endpoint

Before using an API to call resources, you need to specify its region and endpoint. For more details, see the description about Regions and Endpoints.