Changing the AZ of a Standby DB Instance

Scenarios

You can migrate a standby DB instance to another AZ in the same region as the original AZ. The migration speed is about 150 MB/s. If a large amount of data is written during the migration, there may be a long replication delay between the primary and standby instances after the migration.

Constraints

Primary/standby instances running MySQL 5.6, 5.7, or 8.0 support standby instance migration to another AZ.
Before changing the AZ of a standby instance, ensure that there are enough resources in the primary AZ and new standby AZ.
Batch write operations during peak hours may cause migration failures. To ensure successful migration, perform the migration during off-peak hours.
DDL operations and scheduled events will be suspended during migration. To prevent service interruptions, perform the migration during off-peak hours.
During the migration, snapshots are triggered for instances using cloud disks. But full backups will not be created when the migration is complete.
For details about regions and AZs, see Regions and AZs.

Procedure

Click in the upper left corner and select a region.
Click in the upper left corner of the page and choose Databases > Relational Database Service.
On the Instances page, locate the target DB instance and choose More > Migrate Standby Instance to Another AZ in the Operation column.
On the displayed page, select a target AZ and click Submit.
Check the DB instance status on the Instances page.
- During the migration process, the DB instance status is Migrating standby DB instance. You can view the progress on the Task Center page. For details, see Task Center.
- In the upper right corner of the DB instance list, click to refresh the list. After the migration is complete, the DB instance status will become Available.
- On the Overview page, find AZ and check the AZ hosting the standby DB instance.