User's Manual

Power Management 289
NOTE: In the event of a single PSU failure in this configuration, the remaining PSUs
in the failing grid are marked as Online. In this state, any of the remaining PSUs can
fail without interrupting operation of the system. If a PSU fails, the chassis health is
marked non-critical. If the smaller grid cannot support the total chassis power
allocations then AC redundancy status is reported as No Redundancy and Chassis
health is displayed as Critical.
Power Supply Redundancy Mode
The power supply redundancy mode is useful when redundant power grids are
not available, but you may want to be protected against a single PSU failure
bringing down your servers in a modular enclosure. The highest capacity PSU
is kept in online reserve for this purpose. This forms a Power Supply
redundancy pool.
PSUs beyond those required for power and redundancy are still available and
will be added to the pool in the event of a failure.
Unlike AC redundancy, when power supply redundancy is selected the CMC
does not require the PSU units to be present in any specific PSU slot
positions.
NOTE: Dynamic Power Supply Engagement (DPSE) allows PSUs to be placed in
standby. The standby state indicates a physical state, that of not supplying power.
When you enable DPSE, the extra PSUs may be placed in Standby mode to increase
efficiency and save power.
Figure 9-2. Power Supply Redundancy: Totally 4 PSUs with a failure of one PSU.
Power
Supply
#1
Power
Supply
#2
Power
Supply
#3
Power
Supply
#4
Empty
Slot
#5
Empty
Slot
#6
Chassis DC Power Bus
Dual or Single Power Grid:
Power Supply Redundancy protects against failure
of a single power supply.