Users Guide

PSU Removals With Degraded or No Redundancy Policy
CMC may begin conserving power when you remove a PSU or a PSU AC cable. CMC decreases power to
the lower priority servers until power allocation is supported by the remaining PSUs in the chassis. If you
remove more than one PSU, CMC evaluates power needs again when the second PSU is removed to
determine the firmware response. If power requirements are still not met, CMC may turn off the lower
priority servers.
Limits
• CMC does not support automated power-down of a lower priority server to allow power up of a
higher priority server; however, you can perform user-initiated power-downs.
• Changes to the PSU redundancy policy are limited by the number of PSUs in the chassis. You can
select any of the three PSU redundancy configuration settings listed in Default Redundancy
Configuration.
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 38. 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.
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