The auto failover feature allows you to migrate the Elastic Compute Service (ECS) instances deployed on a dedicated host if the dedicated host fails. The feature minimizes the impact of physical failures on your business. This topic describes how to enable or disable auto failover for a dedicated host.
Background information
After the auto failover feature is enabled for a dedicated host, the ECS instances on the dedicated host are migrated to another host if the dedicated host fails. If the auto failover feature is disabled and your dedicated host fails, you can submit a ticket to apply for a new dedicated host.
Notice
- You cannot perform manual migration of ECS instances on local SSD dedicated hosts such as Local SSD type i2 upon DDH failures. In addition, you cannot perform automatic migration of ECS instances on local SSD dedicated hosts. If local SSD dedicated hosts fail, you can submit a ticket to apply for manual migration. However, the data in the local disk is lost after manual migration.
- After all the ECS instances on a failed dedicated host are migrated to another dedicated host, the host ID and the metadata of the ECS instances remain unchanged. The metadata includes the ID, private IP address, and public IP address of each ECS instance. However, the machine ID of the dedicated host is changed.
Procedure
- Log on to the ECS console.
- In the left-side navigation pane, choose .
- In the top navigation bar, select a region.
- Find the dedicated host that you want to modify. In the Host ID/Name column, move the pointer over the name or ID of the dedicated host. Click the
icon next to the name of the dedicated host. - In the Modify DDH Information dialog box, click
to turn on or turn off Auto Failover. 
- Click OK.
Result
