Dell POWEREDGE M1000E - Manual (Page 212)

Power Conservation and Power Budget
CMC conserves power when the user-configured maximum power limit is reached. When the demand for power
exceeds the user configured System Input Power Cap, CMC reduces power to servers in reverse-priority order. This
allows power for higher priority servers and other modules in the chassis.
If all or multiple slots in the chassis are configured with the same priority level, CMC decreases power to servers in
increasing slot number order. For example, if the servers in slots 1 and 2 have the same priority level, the power for the
server in slot 1 is decreased before that of the server in slot 2.
NOTE: You can assign a priority level to each server in the chassis assigning a number from 1 through 9 for each
server. The default priority level for all servers is 1. The lower the number, the higher the priority level.
The power budget is limited to a maximum value equal to that of the set of three PSUs that is the weakest. If you attempt
to set an AC power budget value that exceeds the
System Input Power Cap value, CMC displays a failure message. The
power budget is limited to 16685 Watts.
Maximum Power Conservation Mode
CMC performs maximum power conservation when:
• Maximum conservation mode is enabled
• An automated command line script, issued by a UPS device, enables maximum conservation mode.
In maximum power conservation mode, all servers start functioning at their minimum power levels, and all subsequent
server power allocation requests are denied. In this mode, the performance of powered on servers may be degraded.
Additional servers cannot be powered on, regardless of server priority.
The system is restored to full performance when the maximum conservation mode is cleared.
Server Power Reduction to Maintain Power Budget
CMC reduces power allocations of lower priority servers when additional power is needed to maintain the system power
consumption within the user-configured
System Input Power Cap . For example, Managing and Monitoring Power 297
when a new server is engaged, CMC may decrease power to low priority servers to allow more power for the new
server. If the amount of power is still insufficient after reducing power allocations of the lower priority servers, CMC
lowers the performance of servers until sufficient power is freed to power the new server.
CMC reduces server power allocation in two cases:
• Overall power consumption exceeds the configurable System Input Power Cap .
• A power failure occurs in a non-redundant configuration.
110V PSUs AC Operation
Some PSUs support operation with 110V AC input. This input can exceed the allowed limit for the branch circuit. If any
PSUs are connected to 110V AC, the user needs to set CMC for normal operation of the enclosure. If it is not set and
110V PSUs are detected, all subsequent server power allocation requests are denied. In this case, additional servers
cannot be powered on, regardless of their priority. You can set CMC to use 110 V PSUs using the Web interface or
RACADM.
Power supply entries are logged to the SEL log:
• When 110V power supplies are detected or removed.
• When the 110V AC input operation is enabled or disabled.
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