Manually Switching Between Primary and Standby DB Instances
Scenarios
If you choose to create primary/standby DB instances, RDS will create a primary DB instance and a synchronous standby DB instance in the same region. You can access the primary DB instance only. The standby instance serves as a backup. You can manually promote the standby DB instance to the new primary instance for failover support.
Precautions
For primary/standby switchovers or other operations involving switchovers, such as instance class changes and minor version upgrades:
If there is any slow SQL statement still running during a primary/standby switchover, the slow SQL connection may be suspended (new connections and other idle connections are not affected). After a period of time, an error is returned to the client. The time when the error is reported is related to the settings of TCP parameters such as keepalives_idle, keepalives_interval, and keepalives_count on the client. For details, see the official documentation.
Constraints
You can switch the primary and standby instances 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
- Log in to the management console.
- Click
in the upper left corner and select a region and a project. - Click Service List. Under Database, click Relational Database Service.
- On the Instances page, click the target primary/standby DB instance.
- In the DB Information area on the displayed Basic Information page, click Switch next to the DB Instance Type field.Notice
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.
- In the displayed dialog box, click OK.
- 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.
- Scenarios
- Precautions
- Constraints
- Procedure