White Paper

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HP Dynamic Power Capping
We use HP Dynamic Power Capping technology in most of the enterprise-class G5 ProLiant servers
and beyond. Dynamic Power Capping uses sophisticated monitoring and control circuitry to prevent
server power from exceeding a preset level. Because Dynamic Power Capping is hardware-based, it
can quickly control sudden surges in power use from servers and prevent tripping even the fastest
circuit breakers used in HP PDUs. You can set a power cap for an individual server from the iLO user
interface. For groups of servers, you can set the power caps from the power management module
within Insight Control.
HP Enclosure Dynamic Power Capping
We designed Enclosure Dynamic Power Capping technology specifically for BladeSystem enclosures.
It lets you set a power cap for an HP BladeSystem Enclosure by using Insight Control (version 2.0 or
later) or Onboard Administrator (firmware version 2.30 or later). The Onboard Administrator
monitors and maintains the power cap for the entire enclosure by adjusting cap levels on individual
server blades. As one server blade becomes busy and another becomes idle, Onboard Administrator
adjusts the individual caps to give each server blade what it needs while maintaining the total
enclosure power below the cap.
Power distribution
Power distribution extends from the utility grid to the branch circuits that deliver power to the IT
equipment. No distribution system is 100% efficient, so some power is lost during this process.
Between 2% and 12% of the power delivered to the data center is lost during distribution from the
utility power grid to the IT devices. The biggest power losses occur each time the distribution system
converts or steps-down the voltage to reach the level required by the IT devices. These power
distribution losses are costly because they don’t perform work and they generate heat that needs to be
extracted.
Follow these two basic power distribution principles to reduce your data center power losses:
Minimize power conversions to reduce power losses and heat generation.
Distribute high voltage power as close to the load as possible. High voltage circuits have lower
transmission losses than low voltage circuits and require a less expensive wiring infrastructure.
Tools and products that improve data center power distribution efficiency, monitoring, and
provisioning include:
HP Intelligent Power Discovery
HP Power Advisor tool
HP uninterruptible power supplies
HP Intelligent Power Discovery
It’s not easy to tell when a circuit is underutilized or potentially overloaded. The former can deprive
your data center of extra revenue, and the latter can lead to unscheduled downtime. It’s also difficult
to detect potential wiring errors that can cause mission-critical server failures. Intelligent Power
Discovery (IPD) removes the guesswork in determining your data center’s power and IT equipment
connectivity (topology). IPD also monitors real-time power use and detects some common wiring
errors.