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Help Center> Relational Database Service> User Guide> Working with RDS for PostgreSQL> Instance Modifications> Changing a DB Instance Type from Single to Primary/Standby
Updated at: Apr 02, 2022 GMT+08:00

Changing a DB Instance Type from Single to Primary/Standby


  • RDS enables you to change single DB instances to primary/standby DB instances to improve instance reliability. This operation affects network and disk I/O operations of the primary DB instance.
  • 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 primary and standby DB instances in different AZs for high availability and disaster recovery.
  • Anti-affinity deployment is supported for primary/standby DB instances to prevent the entire instance unavailability due to the failure of a single host.


  1. Log in to the management console.
  2. Click in the upper left corner and select a region and a project.
  3. Click in the upper left corner of the page and choose Database > Relational Database Service. The RDS console is displayed.
  4. On the Instance Management 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.

  5. 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 achieve failover and high availability.

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

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