When all nodes of the primary instance in a Global Active Database (GAD) instance group become unavailable, promote a secondary instance to take over as the new primary. Before the switchover, the secondary instance handles read requests only. After the switchover, the new primary instance handles both read and write requests, restoring full application workloads. Use this operation for disaster recovery (DR) drills and geo-disaster recovery switchovers.
Prerequisites
Before you begin, ensure that:
The GAD instance group is in the Running state.
The GAD instance group is a DR instance group. For differences between a DR instance group and an active geo-redundancy instance group, see DR and active geo-redundancy.
Potential impacts
This switchover is a forced operation with irreversible consequences. Understand the following impacts before proceeding:
Data loss: A forced primary/secondary switchover may cause data loss.
Brief connection interruptions: Transient connections may occur during the switchover. Configure your application to automatically reconnect, and perform the switchover during off-peak hours.
Instances removed from the group: After the switchover completes, the original primary instance and all remaining secondary instances are removed from the GAD instance group. Their Data Transmission Service (DTS) data synchronization task is interrupted.
Removed instances remain accessible: The removed instances become independent ApsaraDB RDS for MySQL instances. Instance data and DTS data synchronization accounts are preserved. Find them on the Instances page.
After the switchover, you can re-add the removed instances as secondary instances to rebuild the GAD instance group.
Perform the switchover
Go to the Global Active Instances page.
Find the GAD instance group and click the instance group ID.
In the List of RDS instances section, find the secondary instance to promote and click Switch To Primary Instance in the Actions column.
Review the listed impacts and click Switch.
What to do next
After the switchover completes, evaluate your business requirements and determine whether to update the endpoint in your application to the endpoint of the new primary instance.