Changing a DB Instance Type from Single to Primary/Standby

Scenarios

• RDS enables you to change single DB instances to primary/standby DB instances to improve instance reliability.
• Primary/standby DB instances support automatic failover. If the primary DB instance fails, the standby DB instance takes over services quickly.
• Anti-affinity deployment is supported for primary/standby DB instances to prevent the entire instance unavailability due to the failure of a single host.

Precautions

RDS single DB instances can be changed to primary/standby DB instances, but not the other way around.

Procedure

1. Log in to the management console.
2. Click in the upper left corner of the page and choose Databases > Relational Database Service.
3. On the Instances page, locate a single DB instance and choose More > Change Type to Primary/Standby in the Operation column.

   Alternatively, click the target DB instance. In the DB instance topology, click on the left to change the instance type from single to primary/standby.

4. Select a standby AZ. Other configurations are the same as those of the primary DB instance by default. Confirm the configurations and click Submit.

   It is recommended that the standby AZ be different from the primary AZ to provide failover and high availability.

5. Check the instance status on the Instances page.
   • The DB instance is in the Changing type to primary/standby status. 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 DB instance type is changed to primary/standby, the instance status will change to Available and the instance type will change to Primary/Standby.