Infortrend RAID Controller Manual

12-6
in this configuration should fail, the existing controller will
temporarily take over for the failed controller until it is replaced. The
failover and failback processes are totally transparent to host and
require only physical disconnect and reconnect efforts. Controllers
are hot-replaceable and replacing a failed unit takes only a few
minutes.
Controller Failover and Failback
A. Channel Bus
Here is a sample illustration of the redundant controller operation:
Figure 12 - 7 Redundant Controller Channel Bus
The host computer is connected to both the Primary and
Secondary controllers. Each controller has one of its SCSI/Fibre
channels assigned as the host channel, with the other SCSI/Fibre
channels assigned as the drive channels. There are two logical
drives. Logical drive 0 is assigned to the Primary controller; and
logical drive 1 assigned to the Secondary controller. Should one
controller fail, the existing controller will be able to access the
logical drive belonging to the failed controller via the previously
assigned ID.
Figure 12 - 8 Controller Failover
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