This topic describes the Alibaba Cloud regions and zones that you need to familiarize yourself with when you use networks. This helps you configure and deploy cloud resources and optimize the network performance of instances.
Regions
Regions are geographical locations where Alibaba Cloud data centers are deployed. In most cases, regions are divided based on the cities where the data centers are deployed. For example, the data center of the China (Qingdao) region resides in Qingdao, China.
Zones
Zones are multiple isolated physical areas in a region. Each zone has an independent power supply and network. Only zones in the same region can communicate with each other over the internal network. Resources that are deployed in the same zone share the same network and have minimal latency between each other. Services deployed in the same zone provide faster communication speeds, which translates into more efficient business operations. For example, the China (Qingdao) region has two zones, which are Qingdao Zone B and Qingdao Zone C.
Relationship between regions and zones
A region consists of multiple zones. Zones in the same region are interconnected over a low-latency internal network. Zones in each region are completely isolated from zones in other regions.
The following figure shows the relationships between regions and zones.
In the figure, Region 1 has three zones and Region 2 has three zones.
Create instances in a zone
Before you create an Elastic Compute Service (ECS) instance, select a region and a zone based on your business requirements. Resources in different regions are isolated from each other. When you view your resources, only the resources that are tied to the region that you specify are displayed. A region that is closer to the geographical location of your users provides lower latency and higher access speed.
Create a virtual private cloud (VPC) in the region where you want to create the ECS instance. VPCs are region-specific resources and cannot be deployed across regions. A VPC spans all zones of the region where the VPC resides. For more information, see Overview.
Create a vSwitch to define a subnet in the zone in which you want to create the ECS instance. For more information, see Create and manage a vSwitch. Cloud resources cannot be directly deployed in a VPC, but must be deployed in vSwitches of a VPC. You can create one or more vSwitches in each zone.
After you create a vSwitch in a zone, you can create instances in the zone. For information about the other configurations that are required to create instances, see Create an instance on the Custom Launch tab.
We recommend that you select zones based on your requirements for disaster recovery and network latency.
If your application requires high disaster recovery capabilities, we recommend that you deploy instances in different zones within the same region. If you distribute your instances across multiple zones and one instance fails, you can use an instance in another zone to handle requests.
If your application requires low latency, we recommend that you deploy instances within the same zone.
Migrate instances to a different zone
You can migrate instances from one zone to another zone in the following scenarios: the instance type to which you want to upgrade is unavailable in the current zone, you want to obtain the cross-zone disaster recovery capability, and you want to reduce the call latency between instances across zones.
We recommend that you migrate instances across zones to change the zones of the instances in the following scenarios. For more information, see Create a cross-zone migration job.
The software authorization codes of the instances are associated with media access control (MAC) addresses.
You do not want to change the IDs of the instances and the disks because the IDs are used for business configurations.
You do not want to be charged during migration.
You do not want to change the public IP addresses of the instances because the public IP addresses are used for business configurations.