White Paper

Dell Power Center’s Power Policies for 12
th
-Generation Servers
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minimize the power usage of all the servers in a rack. From the Power Center user interface, the user
navigates to the physical-based group of that rack in Power Center and then applies the EPR feature to
it. Note that EPR is not meant to be used for long periods of time and certain Power Center
configuration features may be disabled during the application of EPR.
Figure 9 shows a rack under EPR. The power usage on the rack’s servers is reduced to a minimum.
Power consumption is reduced due to EPR Figure 9.
Power usage is throttled down in
emergency event
Setting a Low or Untenable Power Cap on the Server
A power policy is a powerful vehicle for controlling power consumption. The user can virtually set the
capping value anywhere between the lower bound and upper bound to restrict the power consumption
of a group of servers. However, Dell does not recommend setting the cap value at or below the
average power consumption. The average power consumption of a server might rise over time for any
number of reasons, including an increase in the workload or increases in fan activity as the
temperature of the server rises. When power consumption reaches or rises above the cap value, Power
Center will attempt to keep the power consumption at the cap value and send an alert that the power
cap is unachievable. Keeping the server at an unachievable cap level will negatively impact the
performance of the server and make the power policy ineffective.
The best practice is to evaluate the trend of power consumption by monitoring the power consumption
through Power Center’s trend-graphing features, and then to set the cap between the average power
consumption and the upper-bound value.