Changing the Failover Priority

Scenarios

RDS gives you control over the failover priority of your primary/standby DB instance. You can set it to Reliability or Availability.

• Reliability (default setting): Data consistency is preferentially ensured during a primary/standby failover. This is recommended for applications whose highest priority is data consistency.
• Availability: Database availability is preferentially ensured during a primary/standby failover. This is recommended for applications that require databases to provide uninterrupted online services.

Primary/Standby Replication Mode

• RDS for SQL Server uses synchronous replication between the primary and standby DB instances by default. SQL Server 2017 Enterprise Edition and 2019 Enterprise Edition use AlwaysOn availability groups (AGs). Other editions use database mirroring.
• RDS for SQL Server uses asynchronous replication between the primary DB instance and read replicas by default.

Procedure

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 Databases > Relational Database Service.
4. On the Instances page, click the primary instance name.
5. In the DB Information area on the displayed Basic Information page, click Change next to the Failover Priority field. In the displayed dialog box, select a priority and click OK.
   Figure 1 Changing the failover priority
   

6. View the results on the Basic Information page.