Changing an AZ

You can migrate an instance to any AZ in the same region.

Clusters and replica sets can be migrated between AZs.
Instances deployed across AZs and associated with an IPv6 subnet do not support this operation.
Inactive standby nodes and read replicas in a replica set instance do not support this operation.

Services will be interrupted for up to 60 seconds while the AZ is being changed. The time required to change an AZ depends on the amount of data to be migrated. The entire migration process may take up to an hour. You are advised to use an HA connection to access the instance or configure your client to automatically reconnect to the instance.
For details about regions and AZs, see Regions and AZs.

**Table 1** Supported migration types and scenarios
Migration Type	Scenario
Migrating data from one AZ to another AZ	DDS instances can be migrated to the AZ to which the ECS belongs. DDS instances and ECS in the same AZ can be connected through a private network with lower network latency.
Migrating data from a single AZ to multiple AZs	The instance disaster recovery capability needs to be improved.

Log in to the management console.
Click in the upper left corner and select a region and a project.
Click in the upper left corner of the page and choose Databases > Document Database Service.
On the Instances page, click the instance name.
In the DB Information area on the Basic Information page, click Change to the right of the AZ field.
On the displayed page, select a desired AZ and click OK.
On the Instances page, check the changed AZ.
- During the changes, the instance status is Changing AZ.
- In the upper right corner of the instance list, click to refresh the list. After the migration is complete, the instance status will become Available.
- In the DB Information on the Basic Information page, view the new AZ where the DB instance is deployed.