HP Insight Control - Manual (Page 25)

Figure 6 Power Summary Meter
While the enclosure may theoretically consume 35 A of power (the Calibrated Max Power based
on the current configuration of the hardware), the maximum power observed since power
management monitoring commenced was only 14 A (Peak Observed Power). The difference
between Calibrated Max Power and Peak Observed Power, 35 A - 14 A = 21 A, represents the
potential power that can be reclaimed when applying the power cap value. Power caps are
supported on both BladeSystem enclosures and many models of HP ProLiant servers. Using a
Dynamic Power Cap value prevents the capped device from using more than the specified amount
of power, even if it involves reducing the performance of the system.
Various HP ProLiant servers support power capping (which limits the thermal output) and Dynamic
Power Capping (which limits the electrical power consumption). If you are attempting to reclaim
thermal capacity or limit the total heat output of a group of systems, either type of cap may be
used. If, however, you are attempting to prevent an electrical overload, be sure that your device
supports dynamic power capping.
Similarly, for example, consider a system say ProLiant ML370 server as shown below:
Figure 7 Example of Power Summary Meter
While the faceplate power is 1000 W, the Calibrated Max Power as measured by the hardware
itself is only 509 W, and based on historical observation of several months, the highest power
consumption ever observed was 432 W. Based on past behavior, there is 70 W (502-432) that
can potentially be reclaimed without noticeably impacting the performance of the system.
When determining an appropriate cap to reclaim capacity, consider the following issues:
Task: Determining trapped capacity in your data center 25