EPA tackling energy efficiency in storage equipment

Agency issues first draft of Energy Star specification one year after announcing the program.

Agency issues first draft of Energy Star specification one year after announcing the program.

by Patrick McLaughlin

Add storage equipment to the list of data center technologies that will soon be part of the United States Environmental Protection Agency’s (EPA) Energy Star program (www.energystar.gov). In April the EPA issued a first draft of the Energy Star Program Requirements for Data Center Storage. As we previously reported, the agency has also established an Energy Star program for computer servers, is about to officially launch a program for data center facilities, and is in the early stages of developing a program for uninterruptible power supplies (UPSs).

On April 9 the EPA sent to all interested stakeholders Draft 1 Version 1.0 of the storage document. In an accompanying letter, Andrew Fanara of the agency’s climate protection partnerships division and Energy Star program manager acknowledged “there are many aspects of Draft 1 that are still to be determined based on the results of ongoing analysis,” and that Draft 1 represents the EPA’s “latest thinking based on stakeholder comments on the specification framework and subsequent meetings with industry.”

Development timeline

To that end, the process the EPA is taking to establish the rating program for data center storage is essentially the same as it has taken for the data center facilities and server programs. It announced the storage program in April 2009; at that time it stated that after market review and discussions with product manufacturers, industry associations and other parties, “EPA concluded that IT purchasers would benefit from access to standardized information about the energy performance of storage equipment made available through the Energy Star program.”

In June 2009 a framework document was established and the next month at a stakeholder meeting that document’s contents were discussed. Over the following months the EPA held a testing workshop for storage equipment, established a data-collection procedure and held a stakeholder information session coinciding with the Green Grid Technical Forum in February 2010. Issuing the first draft of the program’s requirements was the next step in the process, followed by a stakeholder meeting at which the draft was discussed. Official comments on the first draft were due to the EPA by May 21.

Fanara pointed specifically to the efficiency of storage power supply units (PSUs) as an area of continued study for this specification. He said, “With the understanding that storage PSUs are often installed in redundant configurations, EPA intends to focus its efforts on encouraging: 1) the use of PSUs that are most efficient at low loads (<40%); 2) right-sizing of PSUs to application requirements; and 3) novel approaches to achieve overall system efficiencies.”

According to the Storage Networking Industry Association (SNIA; www.snia.org) a power supply unit (or simply power supply) is “a component which converts an AC or DC voltage input to one or more DC voltage outputs for the purpose of powering a system or subsystem. Power supplies may be redundant and hot swappable.” It goes on to say that, “In storage subsystems, power distribution units, power supplies, cooling devices and controllers are often configured to be redundant.”

Much work to be done

Draft 1.0 of the Energy Star specification includes no figures at all for PSU power factor requirements. The draft includes the following note. “EPA will not be implementing Net Power Loss (NPL) requirements in the Version 1.0 specification. During the computer server specification development process, stakeholders expressed broad concern with the approach, both in terms of testing burden and familiarity with the NPL concept in both manufacturer and end user communities. EPA continues to believe that power supply requirements should show the impact of power supply sizing and sourcing practices, and intends to address this in future versions of the specification. EPA also urges further research or pilot programs on NPL to evaluate benefits of the metric to end users.”

The SNIA has been actively involved in each step of the process. The association formed its Green Storage Initiative (GSI) in 2007, so it has been leading storage energy-efficiency efforts for years. The group recently stated, “The SNIA has submitted 31 data sets to the EPA for their data collection project and continues to work closely with the EPA to ensure efforts, initiatives and industry resources are complementary for users. Several member companies use the SNIA as a way to anonymously submit data to the EPA. The SNIA has also shared test data with the EPA for validating power supply efficiency measurement methods.”

While the EPA may have officially issued an initial draft of this specification, it realizes it has significant research and effort ahead of it before it will produce a finished product. PSUs represent just one of several product and technology types the EPA must sort out before it can realistically assign efficiency metrics. Fanara said, “A discussion of storage system software as a contributor to overall system energy is included in … the document. EPA recognizes the energy efficiency potential of software features such as data de-duplication, data compression, delta snapshots and thin provisioning.”

The agency had not even finished Version 1.0 of the specification for computer servers before it began work on Version 2.0. It may take a similar approach with this storage spec.

Patrick McLaughlin is our chief editor.

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