• Relational Database Service

  1. Help Center
  2. Relational Database Service
  3. User Guide
  4. Managing DB Instances
  5. DB Instance Operations
  6. Changing a DB Instance Type from Single to Primary/Standby

Changing a DB Instance Type from Single to Primary/Standby


You can change a DB instance type from single to primary/standby to improve the instance reliability. The original instance resources are retained.


  1. Log in to the management console.
  2. Click in the upper left corner and select a region and a project.
  3. Click Service List. Under Database, click Relational Database Service to go to the RDS console.
  4. On the Instance Management page, select the target DB instance and choose More > Change Type to Primary/Standby in the Operation column.
  5. View the primary and standby DB instance information. By default, the primary DB instance information is the same as that of the original single DB instance. For the standby DB instance, you can select the AZ only. The other configurations cannot be modified and are the same as those of the primary DB instance. For Microsoft SQL Server DB instances, you need to enter the original administrator password and click Submit.

    Primary/standby DB instances support automatic failover. If the primary DB instance fails, the standby DB instance takes over services quickly. You are advised to deploy them in different AZs for high availability and disaster recovery.

  6. After a single DB instance is changed to primary/standby instances, you can view and manage it on the Instance Management page.

    • The DB instance is in the Changing to Primary/Standby status.
    • In the upper right corner of the DB instance list, click to refresh the list. After the DB instance type is changed to primary/standby, the instance status will change to Available and the instance type will change to Primary/Standby.