HP Integrated Lights-Out 2 User Guide

Dynamic power capping for server blades
Dynamic power capping is an iLO 2 feature available for c-Class server blades and accessed
through HP Onboard Administrator. For more information on all the power setting options for
c-Class server blades, see the HP BladeSystem Onboard Administrator User Guide.
Dynamic power capping is only available if your system hardware platform, BIOS (ROM), and
power micro-controller firmware version support this feature. If your system is capable of performing
dynamic power capping, iLO 2 automatically functions in Dynamic Power capping mode.
In Onboard Administrator, there are two Dynamic Power capping options:
• Dynamic Power
If enabled, Dynamic Power automatically places unused power supplies in standby mode to
increase enclosure power supply efficiency, thereby minimizing enclosure power consumption
during lower power demand. Increased power demands automatically return standby power
supplies to full performance. If Dynamic Power is:
— Enabled (default setting) – Some power supplies can be automatically placed on standby
to increase overall enclosure power subsystem efficiency.
— Disabled – All power supplies share the load. The power subsystem efficiency varies
based on load.
• Enclosure Dynamic Power Cap
An optional setting that enables you to set a cap on a group of servers in an enclosure. Set
the cap between the values shown above the Enclosure Dynamic Power Cap field. These
values are based on the enclosure's current configuration.
As the servers run, the demand for power varies for each server. A power cap for each server
is set to provide the server with enough power to meet its workload demands while still
conforming to the Enclosure Dynamic Power Cap.
You can use either the Static Power Limit or the Enclosure Dynamic Power Cap in the following
situations:
— If the facility power is limited to the enclosure, you can enter a fixed limit into each
enclosure. For example, if the hosted location limits the enclosure to 5000 W. In the limit
Enclosure Input Watts field, enter 5000. The Onboard Administrator limits total power
allocation to 5000 W, which might result in denying power to some of the server blades.
— If the facility limits cooling capacity to the enclosure, then divide the limit of Btu/hr
available to the enclosure by 3.41 to determine the watts limit for that enclosure. Enter
that watts limit to restrict the heat load of the enclosures. For example: If the facility limits
individual enclosure to 27,280 Btu/hr, then 27,280 divided by 3.41 yields 8,000 W.
Enter the watts limit to restrict that enclosure to 27,280 Btu/hr. This limit can result in
denying power to some of the server blades.
— If you need to restrict an enclosure's electrical load or thermal output, an Enclosure
Dynamic Power Cap is better. It enables more blades to power on than a Static Power
Limit does. A Static Power Limit is better in the following cases:
– You do not want caps dynamically adjusted on your server blades.
– You prefer to not power on a server blade if it cannot be allocated full power (even
if it typically consumes less).
– More than 1/4 of the blades in the enclosure do not meet hardware or firmware
requirements for the Enclosure Dynamic Power Cap.
– You do not have redundant AC power supplies.
– Do not set a cap on an empty enclosure. This disables both the Static Power Limit
and the Enclosure Dynamic Power Cap.
ProLiant BladeSystem HP Onboard Administrator 127