HP recently announced their new Dynamic Power Capping feature in the HP Thermal Logic portfolio – this offers some great new functionality that I thought well worth a mention.
What is it?
But first, what is Dynamic Power Capping about? This description from HP probably best sums it up:
"Most data centers have limitations on the power and cooling capacity available to support IT equipment. And yet, in many cases capacity is left unused for fear that unexpected peaks in server utilization may trip a circuit breaker. Applying a power cap ensures that your HP ProLiant server or HP BladeSystem enclosure does not use more than the specified number of watts of power and cooling capacity assigned. Because circuits are protected, systems administrators can use power capacity more efficiently and avoid allocating unnecessary power and cooling overhead."
In an HP Blade enclosure such as the C7000 the available power can be pooled and allocated to those servers who require it at the time due to heavier workloads.
Where Dynamic Power Capping can really benefit a company is in it’s ability to eliminate the risk of tripping a circuit breaker used by the server/blade enclosure. As the maximum amount of power that can be drawn by the device is ‘capped’ and therefore a known variable you then know that it will never exceed the limit/rating of the circuit breaker.
The HP Thermal Logic portfolio consists of three capabilities which are made available via the HP Insight Control Environment (ICE) or for Proliant ML and DL servers by having an iLO Advanced License along with a license for Insight Power Manager. *Note: for HP BladeSystem c7000 enclosures a Redundant Onboard Administrator (OA) and N+N redundant AC power configuration is also required to make full use of the Dynamic Power Capping.
The following are the three capabilities mentioned:
- Power Measurement – Offers real-time statistics on the actual power consumption of the Proliant server or BladeSystem enclosure. Historical data (>3 years of peak and average power consumption and server temperature date) is also made available.
- Power Regulation – This enables the conservation of power "without performance impact". It achieves this by:
- Automatically adjusting processor power states (p-states) in accordance with workload requirements.
- Makes use of full processor performance when needed and conserves power for less demanding workloads.
- Dynamic Power Capping – This new feature can limit the amount of power consumed by a server. It achieves this by capping the servers power usage at it’s peak, as opposed to it’s average usage. This assists greatly in sizing your power requirements when adding a new server or blade enclosure and eliminates the risk that unexpected changes in workload or surprise changes in power consumption tripping a circuit breaker..
How much power?
When trying to calculate how much power a Proliant server of BladeSystem enclosure will draw there are a couple of different methods. These are:
Name Plate Value – This is power details (eg: Wattage) provided on the side of a server/enclosure’s power supply. This is maximum theoretical amount of power that the PSU will draw and is in most instances way over what is actually consumed so is not a good value to base power usage/requirements on.
HP Power Calculator – This useful tool, see the links in this HP power related pdf for more details, provides the power requirements of a Proliant server when under a particular load. The value of this estimated load can be manipulated within the calculator and the resultant power requirement value generated. This is a more accurate method of planning your power requirements. *Note: the power calculator generally gives a more conservative estimation.
Available when and on what models?
The good news is that the Dynamic Power Management feature is not limited to new model servers but any HP Proliant 300 G5 (2006 +) series server and above. By applying a firmware update that will be available mid-December 2008 these servers will benefit from this functionality.
Initially Dynamic Power Capping will only be available on Intel based Proliant servers though AMD based servers will be included shortly. There is no date confirmed at the time of writing this article.
Put a cap on the power limit of the server – the dynamic power capping can react fast enough to protect the electrical infrastructure.
The key points of HP Dynamic Power Management are:
- By using Dynamic Power Capping you can "reclaim stranded capacity to power more servers" in the datacenter.
- Eliminate the risk of tripping circuit breakers thereby reducing the risk of unplanned downtime.
- Easier to plan capacity and power requirements in the datacenter
- Power savings – depending on how aggressively and accurately the power management is set then savings in power and cooling can be made. That said users of this feature must be careful they don’t throttle the available power to servers too much else risk limiting the performance of the server!
Click here for more information on HP Dynamic Power Capping.