What Are Regions and AZs?

Concept

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 divided based on 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 specific services for specific tenants.
• An AZ contains one or more physical data centers. Each AZ has independent cooling, fire extinguishing, moisture-proof, and electricity facilities. Within an AZ, compute, network, storage, and other resources are logically divided into multiple clusters. AZs within a region are interconnected using high-speed optical fibers to allow you to build cross-AZ high-availability systems.

Figure 1 shows the relationship between regions and AZs.

Figure 1 Regions and AZs

Huawei Cloud offers cloud services in a variety of regions around the world. You can select a region and AZ as needed.

How to Select a Region?

When selecting a region, consider the following factors:

• Location

  You are advised to select a region close to you or your target users. This reduces the network latency and improves the access speed. However, Chinese mainland regions provide basically the same infrastructure, BGP network quality, as well as operations and configurations on resources. Therefore, if you or your target users are in the Chinese mainland, you do not need to consider the network latency differences when selecting a region.

  The countries and regions outside the Chinese mainland, such as Bangkok and Hong Kong (China), provide services for users outside the Chinese mainland. If you or your target users are in the Chinese mainland, these regions are not recommended due to high access latency.

  • If you or your target users are in Asia Pacific excepting the Chinese mainland, select the CN-Hong Kong, AP-Bangkok, or AP-Singapore region.
  • If you or your target users are in Africa, select the AF-Johannesburg region.
  • If you or your target users are in Europe, select the EU-Paris region.
• Relationship between cloud services

  When using multiple cloud services, pay attention to the following restrictions:

  • ECSs, RDS instances, and OBS buckets in different regions cannot communicate with each other through an internal network.
  • ECSs in different regions cannot be bound to the same load balancer.
• Resource price

  Resource prices may vary in different regions. For details, see Product Pricing Details.

How to Select 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.

Regions and Endpoints

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