Users Guide

• CMC does not support automated power-down of a low-priority server to allow turning-on of a higher priority server; however,
you can perform user-initiated turn-os.
• Changes to the PSU redundancy policy are limited by the number of PSUs in the chassis. You can select any of the two PSU
redundancy conguration settings listed in Default Redundancy Conguration.
New Server Engagement Policy
If a new server that is turned on exceeds the power available for the chassis, CMC may decrease the power to the low-priority
servers. This could happen if the administrator has congured a power limit for the chassis that is below what would be required for
full power allocation to the servers, or if insucient power is available in case higher power requirements by all servers in the chassis.
If enough power cannot be freed by reducing the allocated power of the low-priority servers, the new server is not allowed to turn
on.
This occurs if the administrator had congured power limit for the chassis lower than the full power allocation to the servers or if
insucient power is available to servers requiring high power.
The following table provides the actions taken by CMC, when a new server is powered on in the scenario described earlier.
Table 37. 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
Not Allowed
If a PSU stops functioning, 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, on the basis of 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 have degraded
performance or, in an extrement case, servers may be turned o. Both conditions are in reverse-priority order; that is, the low-
priority servers are turned o rst.
The following table provides the rmware response to a PSU turno, or removal as it applies to various PSU redundancy
congurations.
Table 38. Chassis Impact from PSU Failure or Removal
PSU
Conguration
Dynamic PSU
Engagement
Firmware Response
Grid Redundancy Disabled CMC alerts you about loss of Grid redundancy.
Power Supply
Redundancy
Disabled CMC alerts you about loss of power supply redundancy.
Grid Redundancy Enabled CMC alerts you about loss of Grid Redundancy. PSUs in standby mode (if any) are turned on
to compensate for power budget lost from the PSU failure or removal.
Power Supply
Redundancy
Enabled CMC alerts you of loss of Power Supply Redundancy. PSUs in standby mode (if any) are
turned on to compensate for power budget lost from PSU failure or removal.
Power Supply and Redundancy Policy Changes in System Event Log
Changes in the power supply state and power redundancy policy are recorded as events. Events related to the power supply that
record entries in the system event log (SEL) are power supply insertion and removal, power supply input insertion and removal, and
power supply output assertion and de-assertion.
The following table lists the SEL entries that are related to power supply changes:
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