Manually Switching Between Primary and Standby DB Instances

Scenarios

If the primary node of a primary/standby instance is unavailable due to a VM, disk, or network fault, RDS automatically triggers a primary/standby failover. In addition to automatic failover, you can manually switch between the primary and standby instances for rack-level DR.

Introduction to Primary/Standby DB Instances

A primary/standby instance uses an HA architecture. The primary and standby instances share the same IP address.

• Data is synchronized from the primary instance to the standby instance in real time. You can only access the primary instance. The standby instance serves as a backup.
• When a primary instance is being created, a standby instance is provisioned along with it to provide data redundancy. The standby instance is invisible to you after being created.
• If the primary instance fails, a failover occurs, during which database connection is interrupted. If there is a replication delay between the primary and standby instances, the failover takes an extended period of time. The client needs to be able to reconnect to the instance.

Constraints

• A manual switchover does not change the connection information of the DB instance, including its VPC, subnet, security group, floating IP address, private domain name, and database port.
• A primary/standby switchover may cause a brief interruption of several seconds or minutes (depending on the replication delay). If transaction logs are generated at a speed higher than 30 MB/s, services will probably be interrupted for several minutes. To prevent traffic congestion, perform a switchover during off-peak hours.
• You can perform a switchover only when the following conditions are met:
  • The primary/standby instance is running properly.
  • The primary/standby replication is normal.
  • The replication delay is less than 5 minutes, and the data on the primary and standby instances is consistent.

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, click the target primary/standby instance name to go to the Overview page.
4. Under DB Instance Type, click Switch.
5. In the displayed dialog box, click Yes.
6. After the switchover is successful, check the status of the DB instance on the Instances page.
   • During the switchover, the DB instance status is Switchover in progress.
   • In the upper right corner of the DB instance list, click to refresh the list. After the switchover is successful, the DB instance status will become Available.