Regions

Overview

A region is the physical location of an IDC. In Tencent Cloud, regions are fully isolated from each other, ensuring cross-region stability and fault tolerance. We recommend that you choose the region closest to your end users to minimize access latency and improve access speed.

You can view the following table or use the DescribeRegions API to get a complete list region list.

Characteristics

• The networks of different regions are fully isolated. Tencent Cloud services in different regions cannot communicate via a private network by default.
• Tencent Cloud services across regions can communicate with each other through public IPs over the Internet, while those in different VPCs can communicate with each other through CCN, which is faster and more stable.
• Cloud Load Balancer currently supports intra-region traffic forwarding by default. If you enable the cross-region binding feature, a CLB instance can be bound to CVM instances in another region.

Availability Zones

Overview

An availability zone (AZ) is a physical IDC of Tencent Cloud with independent power supply and network in the same region. It can ensure business stability, as failures (except for major disasters or power failures) in one AZ are isolated without affecting other AZs in the same region. By starting an instance in an independent availability zone, users can protect their applications from being affected by a single point of failure.
You can view the following table or use the DescribeZones API to get a complete availability zone list.

Characteristics

Tencent Cloud services in the same VPC are interconnected via the private network, which means they can communicate using private IPs, even if they are in different availability zones of the same region.

Note：

Private network interconnection refers to the interconnection of resources under the same account. Resources under different accounts are completely isolated on the private network.

China

Other Countries and Regions

How to Select Regions and Availability Zones

When selecting a region and availability zone, take the following into consideration:

• Your location, the location of your users, and the region of the CVM instances.
  We recommend that you choose the region closest to your end users when purchasing CVM instances to minimize access latency and improve access speed.
• Other Tencent Cloud services you use.
  When you select other Tencent Cloud services, we recommend you try to locate them all in the same region and availability zone to allow them to communicate with each other through the private network, reducing access latency and increasing access speed.
• High availability and disaster recovery.
  Even if you have just one VPC, we still recommend that you deploy your businesses in different availability zones to prevent a single point of failure and enable cross-AZ disaster recovery.
• There may be network latency among different availability zones. We recommend that you assess your business requirements and find the optimal balance between high availability and low latency.
• If you need access to CVM instances in other countries or regions, we recommend you select a CVM in those other countries or regions. If you use a CVM instance in China to access servers in other countries and regions, you may encounter much higher network latency.

Resource Availability

The following table describes which Tencent Cloud resources are global, which are regional, and which are specific to availability zones.

Relevant Operations

Migrating an instance to another availability zone

Once launched, an instance cannot be migrated. However, you can create a custom image of your CVM instance and use the image to launch or update an instance in a different availability zone.

1. Create a custom image from the current instance. For more information, see Creating Custom Images.
2. If the instance is on a VPC and you want to retain its current private IP address after the migration, first delete the subnet in the current availability zone and then create a subnet in the new availability zone with the same IP address range. Note that a subnet can be deleted only when it contains no available instances. Therefore, all the instances in the current subnet should be migrated to the new subnet.
3. Create a new instance in the new availability zone by using the custom image you have just created. You can choose the same type and configuration as the original instance, or choose new settings. For more information, see Creating Instances via CVM Purchase Page.
4. If an elastic IP is associated with the original instance, dissociate it from the old instance and associate it with the new instance. For more information, see Elastic IP (EIP).
5. (Optional) If the original instance is pay-as-you-go, you can choose to terminate it. For more information, see Terminating Instances.

Copying images to other regions

Operations such as launching and viewing instances are region-specific. If the image of the instance that you need to launch does not exist in the region, copy the image to the desired region. For more information, see Copying Images.