Regions

Overview

A region is the physical location of an IDC. In Tencent Cloud, different regions are fully isolated, ensuring cross-region maximum stability and fault tolerance. To reduce access latency and increase download speeds, we recommend you select the region nearest to your end users.

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

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 that is faster and steadier.
• Cloud Load Balancer currently supports intra-region traffic forwarding by default. If the cross-region binding feature is enabled, a CLB instance can be bound to CVM instances in another region.

Availability Zones

Overview

An availability zone is a physical IDC of Tencent Cloud with independent power supply and network resource in a single region. It can ensure business stability, as failures (except for large-scale disaster or major power failure) 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 list of availability zones.

Characteristics

Tencent Cloud services in the same VPC are interconnected through the private network, meaning they can communicate using private IPs, even if they are in different availability zones.

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 users when making the CVM purchase decision to minimize access latency and improve access speed.
• Other Tencent Cloud services you use.
  We recommend that, when you select other Tencent Cloud products, 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 speeds.
• 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 higher 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 countries or regions. If you use a CVM instance in China to access servers in other countries and regions, there may be higher access 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 network environment of the current instance is VPC and the private IP address needs to be retained after migration, you need to delete the subnet in the current availability zone and then create a subnet in the new availability zone with the same IP address range as that of the original subnet. Note that a subnet can be deleted only when it does not contain 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 instance type and configuration as that of the original instance, or choose new configurations. 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 instance billing mode of the original instance is pay-as-you-go, you can 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, the image needs to be copied to the desired region. For more information, see Copying Images.