User's Manual

220 Power Management
this mode, the CMC will report three supplies as online and the other three
supplies as redundant, but the load is shared across all six supplies. This is
done to ensure that system does not experience downtime in the event of a
failure. If any of the three PSUs in a grid fail, the CMC will report the other
grid as Online and the enclosure redundancy status will change to No. E-
mail and/or SNMP alerts will be sent to administrators if the Redundancy
Lost or Redundancy Degraded event has been configured for alerting.
NOTE: In the event of a single PSU failure in this configuration, the two remaining
PSUs in the failing grid will be marked as Redundant. In this state, either of the
remaining PSUs can fail without interrupting operation of the system. However, the
redundancy status of the chassis will reflect that AC Redundancy has been
degraded after the first failure.
Power Supply Redundancy Mode
The power supply redundancy mode is useful when redundant power grids are
not available, but users want to be protected against a single PSU failure
bringing down their servers in a modular enclosure.
A datacenter without multiple power grids available should choose a three
power supply configuration, with an additional power supply purchased and
installed as a spare, and set the redundancy policy to Power Supply
Redundancy in the CMC. This option keeps an additional PSU engaged at
all times to ensure that the failure of a single PSU can always be tolerated.
In this mode, three PSUs will be set to Online, and additional PSUs will be
marked Redundant. The Enclosure Redundancy status will change to No,
and alerts will be sent, in the event a PSU failure brings the healthy PSU
count to three or less.
No Redundancy Mode
The no redundancy mode is the factory default setting, and indicates that the
chassis does not have any power redundancy configured. In this
configuration, the overall redundancy status of the chassis will always indicate
No Redundancy.
NOTE: The first three PSUs in the chassis will be listed as Online, and any
additional PSUs will be marked as Redundant.