Users Guide

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 allows more power for the new server. This happens if:
• The administrator had configured a power limit for the chassis that is below the power required for full power allocation to the
servers.
• Insufficient power is available for the worst-case power requirement of all servers in the chassis.
If enough power cannot be freed by reducing the power allocated to the lower priority servers, the new server may not be allowed
to turn on.
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 also allowed to turn on.
The following table provides the actions taken by CMC when a new server is turned on in the scenario described earlier.
Table 39. 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
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 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.
The following table provides the firmware response to a PSU power down or removal as it applies to various PSU redundancy
configurations.
Table 40. Chassis Impact from PSU Failure or Removal
PSU Configuration Dynamic PSU
Engagement
Firmware Response
Grid Redundancy Disabled CMC alerts you of loss of Grid Redundancy.
Power Supply Redundancy Disabled CMC alerts you of loss of Power Supply Redundancy.
No Redundancy Disabled Decrease power to low priority servers, if needed.
Grid Redundancy Enabled CMC alerts you of 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.
No Redundancy Enabled Decrease power to low priority servers, if needed.
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.
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