Chapter 2. Redundant ac-power switch
The redundant ac-power switch is an optional feature that makes the SAN Volume
Controller nodes resilient to the failure of a single power circuit. The redundant
ac-power switch is not a replacement for an uninterruptible power supply. You
must still use a uninterruptible power supply for each node.
You must connect the redundant ac-power switch to two independent power
circuits. One power circuit connects to the main power input port and the other
power circuit connects to the backup power input port. If the main power to the
SAN Volume Controller node fails for any reason, the redundant ac-power switch
automatically uses the backup power source. When power is restored, the
redundant ac-power switch automatically changes back to using the main power
source.
Place the redundant ac-power switch in the same rack as the SAN Volume
Controller node. The redundant ac-power switch logically sits between the rack
power distribution unit and the 2145 UPS-1U.
You can use a single redundant ac-power switch to power one or two SAN Volume
Controller nodes. If you use the redundant ac-power switch to power two nodes,
the nodes must be in different I/O groups. In the event that the redundant
ac-power switch fails or requires maintenance, both nodes power off. Because the
nodes are in two different I/O groups, the hosts do not lose access to the back-end
disk data.
For maximum resilience to failure, use one redundant ac-power switch to power
each SAN Volume Controller node.
Figure 16 shows a redundant ac-power switch.
Redundant ac power environment requirements
Ensure that your physical site meets the installation requirements for the
redundant ac-power switch.
svc00297
Figure 16. Photo of the redundant ac-power switch
© Copyright IBM Corp. 2003, 2008
17
E
E
E
E
E
E
