Dubbed HP Dynamic Power Capping, the feature works in concert with ProLiant hardware and HP's own Insight Control Environment software. Last week, HP officials said that the feature would be available by Nov. 17, although on the HP site the feature isn't promised until mid-December. For now, it is available only on HP Intel- and AMD-based x86 servers.
ProLiant servers released prior to 2006 lack this capability.
Jonathan Eunice, the founder and principal IT adviser at Nashua, N.H.-based Illuminata Inc., said HP isn't the first company to come out with a technology that caps power usage. But what he thinks makes Dynamic Power Capping different is its ability to do so on x86 servers at the hardware level.
"One of the things that is unique is the ability to control power on a very electrical basis and not just use a software mechanism," he said. "The hardware constraint can operate extremely quickly and therefore protect the power equipment and not draw more than what is available. With the software mechanism, generally it's good. But in peak utilization, it could take many seconds for the power to be brought down."
"It's the same idea as hardware partitioning compared to software partitioning," he added. "With hardware partitioning, you can do that via electrical isolation."How Dynamic Power Capping works
When data centers provision servers, they frequently allocate power resources according to the maximum power that the server manufacturer says that server will use, as demarcated on the server's faceplate.
But faceplate data is known for wildly overstating how much power most servers actually use. As a result, data center managers end up allocating more power than they need to.
Dynamic Power Capping gathers a server's actual power usage measurements and then reallocates power accordingly.
"It allows people to say, 'Look, I understand what peak load is over the past two months. I can cap to that peak and can then guarantee that the application has the power to perform at that peak and safely be able to maintain that stable workload,'" said Mark Linesh, HP's VP for enterprise server and storage software.
But here's the catch. Users have to decide how long the machine runs at faceplate value to determine its peak load and corresponding power cap. If peak load is set too low, applications could be handcuffed. Say, for example, an IT manager working for a retail company sets a power cap in June on a server after it has run for two months. What happens during peak retail season between Thanksgiving and Christmas when the server needs more power?
"You should be cautious with all chainsaws," Eunice said. "Any kind of control with workload management or performance management has the power to narrow how much resources you give. If you set the policy wrong, the application could run slower."Other Hewlett Packard announcements
In conjunction with Dynamic Power Capping, HP also announced the following:
- Energy-efficiency analysis and design service, much of which is culled from the HP acquisition of EYP Mission Critical Facilities last year.
- A redesign of the ProLiant BL460c server blade so it uses 44 fewer watts.
- A new HP 24,000W High Efficiency Hot-Plug Power Supply for its BladeSystem c7000 Enclosure, which HP says is more efficient than previous power supplies for blade chasses.
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