Owner's Manual

Power Management 319
Figure 9-1. 2 PSUs per grid and a power failure on grid 1
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. Figure 9-2 illustrates power supply redundancy mode.
PSUs beyond those required for power and redundancy are still available and
is added to the pool in the event of a failure.
Unlike AC redundancy, when power supply redundancy is selected 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.
Power
Supply
#1
Power
Supply
#2
Empty
Slot
#3
Power
Supply
#4
Power
Supply
#5
Empty
Slot
#6
AC Power Grid #1
AC Power Grid #2
Chassis DC Power Bus