15
The Rear Panel
Dual Controller Models
Dual controller systems are indicated by an “R” in their model number (please refer
to
). Controller A is located on top and controller B at the
bottom for dual controller models. In dual controller configuration, if one controller
fails, the second controller module will take over in a manner that is transparent to
application servers.
A
B
A
B
The top controller (Controller A) is the primary controller. The bottom controller
(Controller B) is the secondary (= redundant) controller which is idle during normal
operation and takes over the management role when Controller A cannot function
properly due to hardware error, controller module removal, etc.
If the failed Controller A restarts or a replacement is installed, Controller A will
temporarily assume the role of the secondary controller.
When the RAID system is rebooted, all system configurations will revert back to the
default state and Controller B returns the primary role to Controller A.
