System information

Advanced Functions
5-21
Controller Failback
If a system is in the controller failover mode, the survival controller will take over the failed controller’s job and process its
own job. When a healthy replacement controller is installed, the system will proceed the failback process. The survival
controller will return the failed controller’s job and sync all states and configuration to the failback controller.
When the redundant mode is established, the heartbeat LED of the failback controller flashes. Never remove or power
down (through the GUI) the survival controller before the failback controller heartbeat LED starts flashing.
• GUI Notification
When one of the controller is failover, the following notification message will be displayed and provide the link to the
backup controller. Click ‘Go to peer controller’s GUI’ to view or configure settings.
When a controller is failback, a pop-up dialog box appears to notify users that the system is doing failback (GUI screen is
polling every 15 seconds). Users can click the OK button when the failback process is finished.
If both controllers are down, the following pop-up dialog box will be displayed to notify the user.
Note
1. Only the tasks belong to the preferred controller will be returned to the failback controller. If you
have changed the preferred controller for tasks to the survival controller, the survival controller
then takes the ownership of those tasks. For more information about preferred controller, see
Owner controller and preferred controller on page 5-12.
2. The replacement must be exactly the same controller as the surviving one, as mentioned
previously.
Figure 5-13 Controller failover and the page redirection message
Figure 5-14 Controller failback message
Figure 5-15 Error message indicates both controller failures