User's Manual

300 Power Management
The highest amount of sustained power required to run the chassis and all of
the servers, including the new one, at full power is the worst-case power
requirement. If that amount of power is available, then no servers are
allocated power that is less than the worst-case power needed and the new
server is allowed to power up.
If the worst-case power requirement cannot be met, power is reduced to the
lower priority servers until enough power is freed to power up the new server.
Table 9-2 describes the actions taken by the CMC when a new server is
powered on in the scenario described above.
If a PSU fails, it results in a non-critical health state and a PSU failure event is
generated. The removal of a PSU results in a PSU removal event.
If either event results in a loss of redundancy, based on power allocations,
a loss of redundancy event is generated.
If the subsequent power capacity or the user power capacity is greater than
the server allocations, servers will have degraded performance or, in a worse
case, servers may be powered down. Both conditions are in reverse-priority
order, that is, the lower priority servers are powered down first.
Table 9-3 describes the firmware response to a PSU power down or removal as
it applies to various PSU redundancy configurations.
Table 9-2. CMC Response When a Server Power-On is Attempted
Worst Case Power
is Available
CMC Response Server
Power On
Yes No power conservation is required Allowed
No Perform power conservation:
• Power required for new server is available
• Power required for new server is not available
Allowed
Disallowed
Table 9-3. Chassis Impact from PSU Failure or Removal
PSU Configuration Dynamic PSU
Engagement
Firmware Response
AC Redundancy Disabled CMC alerts you of loss of AC Redundancy.