UNITED STATES ENVIRONMENTAL PROTECTION AGENCYWASHINGTON, D.C. 20460
OFFICE OF
AIR AND RADIATIONMarch 21st, 2013
Dear Data Center Storage Manufacturer or Other Interested Party:
The U.S. Environmental Protection Agency (EPA) welcomes your input on the attached Draft 4 Version
1.0 ENERGY STAR® Data Center Storage specification. Comments on Draft 4 are due to EPA no later
than April 19th.
Since the release of Draft 3, EPA has worked with a wide range of stakeholders to revise and clarify theapproach associated with this new ENERGY STAR product category. Due to the complexity of thespecification, a detailed list of notable changes is included below. Please refer to the attachedspecification and test method documents to review these changes, as well as a number of more minor
alterations from Draft 3 that are not listed below.
Draft 4 includes the Version 2.0 SNIA EmeraldTM test specification, enabling the testing of systems withcaching, which expands the ability of manufacturers to demonstrate system performance. EPA is awareof ongoing testing to verify the performance of some aspects of the Version 2.0 Emerald test specification
and will analyze the results of this testing to decide if a reversion to the Version 1.0 Emerald test
specification is necessary in the Final Draft of the ENERGY STAR Data Center Storage specification.
Draft 4 also enables a greater range of qualifying systems through the optional expanded maximum
qualified configuration and the inclusion of scale-out systems in scope. It also removes the proposed 10%
PSU load point requirements to reduce unnecessary testing burden and cleans up the storage device
replacement requirements to make them clearer, simpler, and more effective. Please see the list below
for details on many of the changes in the document:••Definitions:o 1.E: Computer server definition updated to align with the Final Draft Version 2.0
ENERGY STAR Computer Server specification.
o 1.I.3 and 1.I.4: Clarified the definitions of maximum and minimum ENERGY STAR
qualified configurations to avoid confusion with actual, sellable max and minconfigurations of a product. Also added additional clarifications on drawer rounding forOnline 3 and 4 systems.
o 1.I.5: Added an optional expanded maximum qualified configuration, to complement theexisting expanded minimum and allow stakeholders to qualify a larger range of products
if performance is maintained. Changed the allowable performance deviation from theOptimal Configuration from 10% to 15%.
o 1.I.9: Clarification added to Capacity Optimization configurations. A Capacity
Optimization configuration may only be submitted as an addition to one or more otheroptimizations.
o 1.J.1 and 1.J.2: Replaced definitions of scale-up (now “centralized controller storage”)
and scale-out (now “distributed controller storage”) to provide a clearer differentiation
between the two dominant system architectures in the current market.
Scope:
o 2.1.1.iv.a: To allow newer storage architectures to qualify, the RAID-only requirementfrom Draft 3 is replaced by a more general requirement to use controllers with advanced
data recovery capabilities.

2.1.1.iv.c: After discussions with stakeholders, scale-up (centralized controller storage)
and scale-out (distributed controller storage) systems are now both in scope.
Qualification Criteria:o 3.2.1.i: Removed the 10% PSU load efficiency requirements. Existing data shows thatmost PSUs can meet the levels proposed in Draft 3 but are not routinely tested at the10% load point, necessitating burdensome additional testing for components that arealready efficient. Stakeholders may optionally submit this data if they choose.
o 3.3.1: Clarified that manufacturers that qualify Online 4 systems using modeled data
must make a performance/watt modeler available to qualified purchasers of theirproducts.
o 3.4.1.i: Revised the Parity RAID requirement to allow controllers with advanced data
recovery capabilities.
o 3.4.1.ii: Clarified that systems using passive cooling are not required to meet theadaptive cooling requirement.
o 3.4.2: The minimum number of COMs required to be made available has been changed
to Online2: 0, Online3: 1, and Online4: 1, as there are a number of efficient systems on
the market that have only one COM available.
o 3.5.3: Table 5 and associated language has been updated to use the Version 2.0 SNIA
TM
Emerald specification, including the new Hot Band workload.
o 3.5.4: Workload weighting requirements in Table 6 have been revised to include the newHot Band workload. Further discussions with stakeholders have led to the revision of theremaining weightings in this table to make them more representative of deployed system
workloads.
o 3.5.5 and 3.5.6: Additional clarifications for testing scale-up (centralized controllerstorage) and scale-out (distributed controller storage) systems have been added.
Clarifying language for verifying the presence of COMs has also been added to reduce
unnecessary testing.
o 3.5.7: New language proposing specific test requirements for scale-out (distributedcontroller storage) systems has been added.
o 3.6: Based on stakeholder feedback, the storage device replacement requirements havebeen reorganized and simplified to make them clearer and more useful to both the EPAand manufacturers.
o 3.7.1: Based on stakeholder feedback and data, EPA removed the standard
performance data measurement and output requirements for Online 2 systems. The costof implementing these features is currently too high in proportion to the cost of the systemitself.
o 3.7.3: The language on sampling requirements has been transferred from the Version
2.0 Computer Server Final Draft specification, with modifications to make inlet airtemperature reporting optional.
Test Method:o To harmonize with the SNIA Emerald specification, EPA has removed dc testing
requirements, added three-phase requirements, and harmonized test frequency
requirements with the ENERGY STAR Version 2.0 Computer Servers test method.
o To incorporate the new Hot Banding workload, the test method now references SNIA
Emerald Power Efficiency Measurement Specification Version 2.0 Rev 1.
o After discussion with stakeholders, EPA has removed the 24-hour idle test requirement
and harmonized with the SNIA Emerald specification.
o••EPA will host a webinar on April 2nd at 1:00 PM EST. The agenda will be focused on changes
introduced in Draft 4. Please RSVP to storage@energystar.gov no later than March 29th with thesubject "RSVP – Storage Draft 4 specification meeting."
Stakeholders are encouraged to review the Draft 4 specification and send comments tostorage@energystar.gov no later than April 19th. For further information on specification development
activities to date, visit the ENERGY STAR Product Development website atwww.energystar.gov/NewSpecs and follow the link for “Data Center Storage.”Thank you for your continued support of the ENERGY STAR program. Please direct any specificquestions to RJ Meyers, EPA, at Meyers.Robert@epa.gov, or 202-343-9923; or John Clinger, ICF
International, at John.Clinger@icfi.com, or 215-967-9407.
Sincerely,

Robert Meyers
Data Center Product Manager
ENERGY STAR for Storage