 ENERGY STAR® Program Requirements 
 Product Specification for  
 Data Center Storage 
  Eligibility Criteria 
 Draft 1, Version 2.0 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 1 of 16 
Following is the Draft 1, Version 2.0 ENERGY STAR Product Specification for Data Center Storage. A 1 
product shall meet all of the identified criteria if it is to earn the ENERGY STAR. 2 
1 DEFINITIONS 3 
A. Product Types: 4 
1) Storage Product: A fully-functional storage system that supplies data storage services to 5 
clients and devices attached directly or through a network. Components and subsystems that 6 
are an integral part of the storage product architecture (e.g., to provide internal 7 
communications between controllers and disks) are considered to be part of the storage 8 
product. In contrast, components that are normally associated with a storage environment at 9 
the data center level (e.g., devices required for operation of an external SAN) are not 10 
considered to be part of the storage product. A storage product may be composed of 11 
integrated storage controllers, storage devices, embedded network elements, software, and 12 
other devices. For purposes of this specification, a storage product is a unique configuration 13 
of one or more SKUs, sold and marketed to the end user as a Storage Product.  14 
2) Storage Device: A collective term for disk drives (HDDs), solid state drives (SSDs), tapes 15 
cartridges, and any other mechanisms providing non-volatile data storage. This definition is 16 
specifically intended to exclude aggregating storage elements such as RAID array 17 
subsystems, robotic tape libraries, filers, and file servers. Also excluded are storage devices 18 
which are not directly accessible by end-user application programs, and are instead 19 
employed as a form of internal cache. 20 
3) Storage Controller: A device for handling storage request via a processor or sequencer 21 
programmed to autonomously process a substantial portion of I/O requests directed to 22 
storage devices (e.g., RAID controllers, filers). 23 
B. Storage Product Connectivity: 24 
1) Direct-attached Storage (DAS): One or more dedicated storage devices that are physically 25 
connected to one or more servers.  26 
2) Network Attached Storage (NAS): One or more dedicated storage devices that connect to a 27 
network and provide file access services (File I/O) to remote computer systems.  28 
3) Storage Area Network (SAN): A network whose primary purpose is the transfer of data 29 
between computer systems and storage products. A SAN consists of a communication 30 
infrastructure, which provides physical connections, and a management layer, which 31 
organizes the connections, storage controllers / devices, and computer systems so that data 32 
transfer is secure and robust.  The term SAN is usually (but not necessarily) identified with 33 
block I/O services rather than file access services. 34 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 2 of 16 
C. Capacity Optimizing Methods (COMs)1: The reduction of actual data stored on storage devices 36 
through a combination of hardware and / or software. Common COMs include:  37 
1) Thin Provisioning: A technology that allocates the physical capacity of a volume or file system 38 
as applications write data, rather than allocating all the physical capacity at the time of 39 
provisioning. 40 
2) Data Deduplication: The replacement of multiple copies of data – at variable levels of 41 
granularity – with references to a shared copy in order to save storage space and/or 42 
bandwidth. 43 
3) Compression: The process of encoding data to reduce its size. For the purpose of this 44 
specification, only lossless compression (i.e., compression using a technique that preserves 45 
the entire content of the original data, and from which the original data can be reconstructed 46 
exactly) is recognized.  47 
4) Delta Snapshots: A type of point-in-time copy that preserves the state of data at an instant in 48 
time by storing only those blocks that are different from an already existing full copy of the 49 
data. 50 
D. Storage Taxonomy1: A categorization scheme for use in segmenting the data center storage 51 
market by end-use application and key product characteristics. The major categories of the 52 
taxonomy that are referenced in this document are as follows: 53 
1) Online Storage: Storage products that are intended to service a mixture of Random and 54 
Sequential I/O requests with a short response time. All data stored in Online storage must be 55 
accessible MaxTTFD ≤ 80 ms, unless the storage product is in a Deep Idle state. Online 56 
storage is typically comprised of one or more HDDs or SSDs and a storage controller, and 57 
provides primary data storage to supplement a Computer Server’s internal memory.  58 
2) Near-online Storage: Storage products that are intended to service a mixture of Random and 59 
Sequential I/O requests with a short to moderate response time. Near-online storage 60 
products offer an asymmetrical response; a portion of data may be accessible MaxTTFD ≤ 80 61 
milliseconds, while other data may be accessible MaxTTFD > 80 milliseconds. 62 
3) Virtual Media Library: Storage products that are intended to service primarily Sequential I/O, 63 
with a short response time. The media in a Virtual Media Library (e.g., HDD, optical disk) is 64 
not designed to be physically removed from the system. All data stored in the Virtual Media 65 
Library must be assessable MaxTTFD ≤ 80 ms, unless the storage product is in a Deep Idle 66 
state. Virtual Medial Libraries are intended primarily for moderate and long term data storage. 67 
4) Removable Media Library: Storage products that are intended to service primarily Sequential 68 
I/O, with a moderate to long response time. The media (e.g., tape cartridge, optical disk) in a 69 
Removable Media Library is designed to be physically removed from the storage product. 70 
Removable Media Libraries are intended primarily for long term data archiving. 71 
E. Other Data Center Equipment: 72 
1) Computer Server: A computer that provides services and manages networked resources for 73 
client devices (e.g., desktop computers, notebook computers, thin clients, wireless devices, 74 
PDAs, IP telephones, other computer servers and other network devices). A computer server 75 
is sold through enterprise channels for use in data centers and office/corporate environments. 76 
A computer server is primarily accessed via network connections, versus directly-connected 77 
user input devices such as a keyboard or mouse. For purposes of this specification, a product 78 
must meet all of the following criteria to be considered a computer server:  79 
1 The ENERGY STAR storage taxonomy and COM references in this document are consistent with the terminology developed by the Storage Networking Industry Association Green Storage Initiative as defined in “SNIA EmeraldTM Power Efficiency Measurement Specification” Version 3.0.3. Further detail may be found at www.snia.org/green. 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 3 of 16 
i) is marketed and sold as a Computer Server; 80 
ii) is designed for and listed as supporting computer server operating systems (OS) and/or 81 
hypervisors; 82 
iii) is targeted to run user-installed applications typically, but not exclusively, enterprise in 83 
nature; 84 
iv) provides support for error-correcting code (ECC) and/or buffered memory (including both 85 
buffered DIMMs and buffered on board (BOB) configurations)  86 
v) is packaged and sold with one or more ac-dc or dc-dc power supplies; and 87 
vi) is designed such that all processors have access to shared system memory and are 88 
visible to a single OS or hypervisor.  89 
2) Network Equipment: A device whose primary function is to provide data connectivity among 90 
an arbitrary combination of devices connected to its several ports. Data connectivity is 91 
achieved via the routing of data packets encapsulated according to Internet Protocol, Fibre 92 
Channel, InfiniBand or other standard protocol. Examples of network equipment commonly 93 
found in data centers are routers and switches. 94 
Note: EPA has removed the Version 1.1 definitions for Power Distribution Unit and Intelligent Power 95 
Distribution Units. The use of iPDUs to meet the requirements in Section 3.7 is no longer permitted.     96 
3) Blade Storage: A storage product that is designed for use in a blade chassis. A blade storage 97 
product is dependent upon shared blade chassis resources (e.g., power supplies, cooling) for 98 
operation.   99 
4) Cache: Temporary storage used to transparently store transitory data and which is not 100 
directly addressable by end-user applications.  Primarily used for expediting access to or from 101 
(typically) slower devices.  102 
F. Capacity: Capacity is reported in units of either binary bytes (1 MiB = 1,048,576 Byte) or decimal 103 
bytes (1 MB = 1,000,000 Byte). 104 
1) Assigned Capacity: The amount of space on a system or data container which has been 105 
allotted to be written by an end user or application. (Note: For thin provisioning systems, an 106 
assigned capacity number represents a promise that that amount of space will be provided on 107 
demand; usable capacity is allocated as the container is written too. For fully-provisioned 108 
systems, usable capacity must be committed at the same time the container is allocated.) 109 
2) Effective Capacity: The amount of data stored on a storage product, plus the amount of 110 
unused formatted capacity in the system. 111 
3) Formatted (Usable) Capacity: The total amount of bytes available to be written after a storage 112 
product or storage device has been formatted for use (e.g., by an object store, file system or 113 
block services manager). Formatted capacity is less than or equal to raw capacity. It does not 114 
include areas set aside for system use, spares, RAID parity areas, checksum space, host- or 115 
file system-level remapping, "right sizing" of disks, disk labeling and so on. However, 116 
formatted capacity may include areas that are normally reserved – such as snapshot set-117 
asides – if these areas may be configured for ordinary data storage. 118 
4) Free Space: The amount of unused, formatted capacity as reported by the storage product. 119 
5) Raw (Addressable) Capacity: The sum total amount of addressable capacity of the storage 120 
devices in a storage product. The raw capacity of a storage device is commonly understood 121 
to be the number of bytes available to be written via SCSI or equivalent protocol. It does not 122 
include unaddressable space, ECC (error correcting code) data, remap areas, inter-sector 123 
gaps, etc. 124 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 4 of 16 
G. Operational States: 125 
1) Active State: The state in which a storage product is processing external I/O requests. 126 
2) Idle State: An operational state in which the storage product is capable of completing I/O 127 
transactions, but no active I/Os are requested or pending. The system may, however, be 128 
servicing self-initiated I/Os from background data protection and cleansing, and other 129 
operations not initiated by the user. 130 
i) Ready Idle: The state in which a storage product is able to respond to arbitrary I/O 131 
requests within the MaxTTFD limits for its taxonomy category, but is not receiving 132 
external I/O requests. The storage product may perform routine housekeeping tasks 133 
during Ready Idle, provided such operations do not compromise the product’s ability to 134 
meet MaxTTFD requirements. 135 
ii) Deep Idle: A state in which one or more storage product components or subsystems have 136 
been placed into a low-power state for purpose of conserving energy. A storage product 137 
in Deep Idle may not be able to respond to I/O requests within the MaxTTFD limits for its 138 
taxonomy category, and may need to perform a managed ‘wake-up’ function in order to 139 
return to a Ready Idle or Active State. Deep Idle capability must be a user-selected, 140 
optional feature of the storage product. 141 
H. Power Supply Unit (PSU): A device that converts ac or dc input power to one or more dc power 142 
outputs for the purpose of powering a storage product. A storage PSU must be self-contained 143 
and physically separable from the system and must connect to the system via a removable or 144 
hard-wired electrical connection. Note: Storage PSUs may be Field Replaceable Units (FRUs), 145 
but in some cases may be further integrated with the storage product. 146 
1) Ac-dc Power Supply: A PSU that converts line-voltage ac input power into one or more dc 147 
power outputs. 148 
2) Dc-dc Power Supply: A PSU that converts line-voltage dc input power to one or more dc 149 
power outputs. For purposes of this specification, a dc-dc converter (also known as a voltage 150 
regulator) that is internal to a storage product and is used to convert a low voltage dc (e.g., 12 151 
V dc) into other dc power outputs for use by storage product components is not considered a 152 
dc-dc power supply. 153 
3) Single-output Power Supply: A PSU that is designed to deliver the majority of its rated output 154 
power to one primary dc output. Single-output PSUs may offer one or more standby outputs 155 
that remain active whenever connected to an input power source. For purposes of this 156 
specification, the total rated power output from all additional PSU outputs that are not primary 157 
or standby outputs shall be less than or equal to 20 watts. PSUs that offer multiple outputs at 158 
the same voltage as the primary output are considered single-output PSUs unless those 159 
outputs (1) are generated from separate converters or have separate output rectification 160 
stages, or (2) have independent current limits. 161 
4) Multi-output Power Supply: A PSU that is designed to deliver the majority of its rated output 162 
power to more than one primary dc output for the purpose of powering a storage product. 163 
Multi-output PSUs may offer one or more standby outputs that remain active whenever 164 
connected to an input power source. For purposes of this specification, the total rated power 165 
output from all additional PSU outputs that are not primary and standby outputs must be 166 
greater than or equal to 20 watts. 167 
5) Redundant Power Supplies: Two or more PSUs that are configured to maintain uninterrupted 168 
output load in the event of failure of one PSU. 169 
I. Product Family: A group of models/configurations that share a set of common attributes that are 170 
variations on a basic design. 171 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 5 of 16 
1) Common Product Family Attributes: A set of features common to all models/configurations 172 
within a product family that constitute a common basic design. All models/configurations 173 
within a product family must share the following: 174 
i) made by the same manufacturer; 175 
ii) be from the same model line or machine type; 176 
iii) utilize the same model of storage controller; 177 
iv) fall under the same taxonomy category; and 178 
v) contain equal or greater amount of cache than the corresponding certified configuration. 179 
2) Optimal Configuration: A product configuration which is representative of a product’s 180 
maximum peak energy efficiency performance (performance/watt) for a given workload type. 181 
This configuration represents all products certified within the family under the associated 182 
workload type specified. This configuration  is provided by the manufacturer and may be 183 
optimized for the following workload types: 184 
i) Transaction (Block I/O products only): A workload optimized for random I/O usage 185 
measured in I/O per second per watt; 186 
ii) Streaming (Block I/O products only): A workload optimized primarily for sequential I/O 187 
usage, measured in MiB per second per watt;  188 
iii) Composite (File I/O products only): A workload optimized for mixed I/O usage, measured 189 
in MiB per second per watt.  190 
Note: EPA has proposed several edits under the Product Family definition.  These edits were proposed in 191 
the previously released Discussion Guide and received stakeholder support, including: 192 
- Minor revisions to the Optimal Configuration definition to clarify that it represents all products within the 193 
family.  194 
- Removal of definitions for fixed and flexible certification ranges, capacity workload type, and capacity 195 
optimization family restriction. In addition, the guidance for systems composed of both single and multiple 196 
device types was removed.  197 
A given optimal configuration point will represent all certified systems of that specific workload type within 198 
a product family, with a maximum of three optimal point submissions within a family to represent 199 
transaction, streaming, and composite workload optimized products.  200 
J. Other Definitions: 201 
1) Scale-Up Storage: A storage product comprised of a discreet storage controller (with or 202 
without redundancy), which has a full view of all the storage devices in the storage product. 203 
Incremental storage capacity is added by the addition of storage devices under the control 204 
of the existing storage controller. 205 
2) Scale-Out Storage: A storage product capable of being comprised of two or more discreet 206 
storage controllers (with or without redundancy), combined with an overall integration or 207 
aggregation function resulting in a single storage product view for attached servers.  Each 208 
discreet storage controller often has a partial view to a partition of the overall system's 209 
storage devices, but this is not a fixed requirement.  Incremental storage capacity is added 210 
by the addition of storage devices under the control of the existing storage controller(s) 211 
and/or addition of additional storage devices along with additional controller(s). 212 
Note: With the removal of the section of the Product Family definition specific to systems with multiple 213 
device types, the Automated Storage Tiering definition from Version 1.1 is no longer relevant. As such, 214 
EPA has removed this definition in Draft 1.  215 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 6 of 16 
3) Field-replaceable Unit (FRU): A unit, or component of a system that is designed to be 216 
replaced “in the field;” i.e., without returning the system to a factory or repair depot. Field 217 
replaceable units may either be customer-replaceable, or their replacement may require 218 
trained service personnel. 219 
4) High-availability (HA): The ability of a system to perform its function continuously (without 220 
interruption) for a significantly longer period of time than the reliabilities of its individual 221 
components would suggest. High availability is most often achieved through failure 222 
tolerance.  223 
5) Maximum Time to First Data (MaxTTFD): The maximum time required to start receiving 224 
data from a storage product to satisfy a read request for arbitrary data. 225 
6) RAS Features: An acronym for reliability, availability, and serviceability features. RAS is 226 
sometimes also expanded to RASM, which adds “Manageability” criteria. The three primary 227 
components of RAS as related to storage products are defined as follows: 228 
i) Reliability Features: Features supporting a storage product’s ability to perform its 229 
intended function without interruption due to component failures. Technologies applied to 230 
increase reliability include: component selection (MTBF), redundancy (both at a micro 231 
and macro levels), temperature and/or voltage de-rating, error detection and correction 232 
technologies. 233 
ii) Availability Features: Features that support a storage product’s ability to maximize normal 234 
operating time and minimize planned and unplanned down time.  235 
iii) Serviceability Features: Features that support a storage product’s ability to be serviced 236 
(e.g., hot-plugging).  237 
iv) Advanced Data Recovery Capability: A collective term used in this specification to refer to 238 
error detection and correction features such as RAID, mirroring / grid technology, or other 239 
comparable advanced error detection and recovery systems  240 
v) Non-disruptive Serviceability: Support for continued availability of data and response 241 
times during all FRU and service operations; including break/fix, code patches, 242 
software/firmware upgrades, configuration changes, data migrations, and system 243 
expansion. 244 
Note: With the removal of the option to submit modeled data in place of physical data in Section 3.6 245 
below, the physical and modeled data definitions from Version 1.1 are no longer relevant and have been 246 
removed in Draft 1.  247 
7) Block I/O Loads: 248 
i) Random Read: Any I/O load in which consecutively issued read requests do not specify 249 
adjacently addressed data. The term random I/O is commonly used to denote any I/O 250 
load that is not sequential, whether or not the distribution of data locations is indeed 251 
random. 252 
ii) Random Write: Any I/O load whose consecutively issued write requests do not specify 253 
adjacently addressed data. The term random I/O is commonly used to denote any I/O 254 
load that is not sequential, whether or not the distribution of data locations is indeed 255 
random. 256 
iii) Sequential Read: An I/O load consisting of consecutively issued read requests to 257 
adjacently addressed data. 258 
iv) Sequential Write: An I/O load consisting of consecutively issued write requests to 259 
adjacently addressed data. 260 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 7 of 16 
v) Hot Band: An I/O load consisting of a collection of read and write requests that models 261 
areas of higher frequency I/O activity over the addressed data. 262 
8) File I/O Loads: 263 
i) DATABASE: An I/O load that simulates an OLTP database Table and Log file scenario.  264 
ii) Software (SW) Build: An I/O load that simulates a large software project compilation or 265 
build phase of an EDA workflow.  266 
iii) Video Data Acquisition (VDA): An I/O load that simulates acquisition of data from a 267 
temporarily volatile source such as surveillance or big data ingestion.  268 
iv) Virtual Desktop Infrastructure (VDI): An I/O load that simulates the workload generated by 269 
a hypervisor to support a heavy steady-state knowledge worker workload.  270 
9) Response Time: The time required for the UUT to complete an I/O request. 271 
10) Unit Under Test (UUT): The storage product being tested. 272 
2 CERTIFYING PRODUCTS 273 
2.1 Included Products 274 
2.1.1 Products that meet all of the following conditions are eligible for ENERGY STAR certification, 275 
with the exception of products listed in Section 2.2: 276 
i. meet the definition of a Storage Product provided in Section 1 of this document; 277 
ii. are comprised of one or more SKUs and be able to be purchased in a single order from a 278 
storage product vendor; 279 
iii. are characterized within the Online 2, 3, or 4 Storage Taxonomy categories2 with the 280 
following additional criteria; 281 
a)  contain a controller with advanced data recovery capability  282 
b)  support Block I/O and/or File I/O storage functions; and 283 
c)  implement scale-up or scale-out storage.  284 
2.2 Excluded Products 285 
2.2.1 Products that are covered under other ENERGY STAR product specifications are not eligible 286 
for certification under the ENERGY STAR Data Center Storage specification. The full list of 287 
specifications currently in effect can be found at www.energystar.gov/specifications.   288 
2.2.2 The following products are specifically excluded from certification under this specification: 289 
i. Personal / Portable Data Storage Products; 290 
ii. Computer Servers; 291 
iii. Blade Storage Products; 292 
iv. Direct Attached Storage Products  293 
v. Storage Products capable of only object based storage;  294 
2 As defined in the “SNIA EmeraldTM Power Efficiency Measurement Specification”, Version 3.0.3. 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 8 of 16 
vi. Storage devices in the following categories of the taxonomy: Near-online, Removable Media 295 
Library, Virtual Media Library, Adjunct Storage Products, and Interconnect Elements; 296 
3 CERTIFICATION CRITERIA 297 
3.1 Significant Digits and Rounding 298 
3.1.1 All calculations shall be carried out with directly measured (unrounded) values. 299 
3.1.2 Unless otherwise specified, compliance with specification limits shall be evaluated using 300 
directly measured or calculated values without any benefit from rounding. 301 
3.1.3 Directly measured or calculated values that are submitted for reporting on the ENERGY STAR 302 
website shall be rounded to the nearest significant digit as expressed in the corresponding 303 
specification limit. 304 
3.2 Power Supply Requirements 305 
3.2.1 Power Supply Units (PSUs): PSUs used in storage products eligible under this specification 306 
shall meet the following requirements when tested using the EPRI Generalized Internal Power 307 
Supply Efficiency Test Protocol, Rev. 6.7.1 (available at 308 
https://www.plugloadsolutions.com/docs/collatrl/print/Generalized_Internal_Power_Supply_Effi309 
ciency_Test_Protocol_R6.7.1.pdf).   310 
3.2.2 Efficiency and Power Factor in Primary Embedded Equipment: Embedded PSUs that power 311 
primary components of the storage product, including controllers and drawers, must meet the 312 
requirements in Table 1 and Table 2.  313 
i. Efficiency: A storage product PSU shall meet efficiency requirements as specified in Error! 314 
Reference source not found.. 315 
Table 1: Efficiency Requirements for PSUs 317 
Power Supply Type Rated Output Power 20% Load 
50% Load 
100% Load 
Multi-output 
(Ac-Dc) All Output Levels 90% 92% 89% 
Single-output 
(Ac-Dc) All Output Levels 90% 94% 91% 
Note: Based on stakeholder feedback on the IPS proposals in the ENERGY STAR Discussion Guide, 318 
EPA is proposing updated IPS requirements that align with 80Plus Gold for multi-output IPSs and 80Plus 319 
Platinum for single-output IPSs. These levels align with the requirements in the 20-100% load points 320 
found in the ENERGY STAR Version 3.0 Computer Server specification. 321 
In addition, EPA has updated the IPS test method reference to the latest revision available, R6.7.1.   322 
ii. Power Factor: A storage product PSU shall meet power factor requirements as specified in 323 
Table 2. 324 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 9 of 16 
Table 2: Power Factor Requirements for PSUs 325 
PSU Type Rated Output Power 20% Load 
50% Load 
100% Load 
Redundant and Non-Redundant Capable 
All Output Levels 0.80 0.90 0.95 
iii. Embedded PSUs that do not power primary components of the storage product are not 326 
subject to PSU requirements.  327 
3.3 Power Modeling Requirements 328 
3.3.1 Power Modeling Presale tool: For systems that certify using modeled data, EPA expects that a 329 
power modeling tool characterizing the storage product will be made available to manufacturer 330 
certified purchasers of the product. The power modeling tool must provide an estimated 331 
energy efficiency performance of a deployed configuration based on user-selected 332 
configuration characteristics. Systems that are certified using modeled data are expected to 333 
make performance/watt data available to manufacturer certified purchasers of the product. 334 
3.4 Energy Efficiency Active State Requirements for Block I/O Systems 335 
3.4.1 To certify for ENERGY STAR, each Optimal Configuration point submitted for a block I/O 336 
storage product or storage product family must meet the following applicable active state 337 
requirements in Table 3 for each workload type for which it is certified. 338 
Table 3: Active State Requirements for Block I/O Storage Products 340 
Workload Type Specific 
Workload Test 
Minimum 
Performance/Watt 
Ratio 
Applicable Units 
of Ratio 
Transaction Hot Band 20.0 IOPS/watt 
Streaming Sequential Read 4.0 MiBS/watt 
Streaming  Sequential Write 4.0 MiBS/watt 
3.4.2 An Optimal Configuration point submitted for a streaming workload must meet either the 342 
sequential read or sequential write requirement in Table 3 above, but is not required to meet 343 
that value for both workload tests. Both test values will be reported and displayed publicly 344 
regardless of whether they meet the criteria in Table 3.    345 
Note: Based on stakeholder feedback on the Discussion Guide, EPA is proposing active state 346 
requirements which differentiate both transaction and streaming optimized products within each Online 347 
category.  The proposed criteria maintain sufficient product variety to allow purchasers to have options 348 
from multiple manufacturers. EPA did investigate setting active state requirements by Online category, 349 
but found it did not provide sufficient additional differentiation in the current data set to implement. EPA 350 
also considered setting levels for File I/O systems, but does not have enough systems in its database at 351 
this time to set appropriate levels.  352 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 10 of 16 
These requirements allow 30-40% of products in most product bins to meet the ENERGY STAR criteria, 353 
which is slightly higher than the Agency’s typical target. EPA has taken this more conservative approach 354 
in recognition of the  limited data set and relatively few number of unique models available on the market 355 
compared to other product types. EPA has not provided savings estimates for these products due to a 356 
lack of information on the actual power consumed by the product. EPA is interested in providing savings 357 
estimates for this specification and solicits stakeholder feedback on whether  power values are available 358 
for products in the ENERGY STAR dataset. These could be provided in aggregate to allow the Agency 359 
the ability to provide stakeholders information on the impact of this specification revision. 360 
In EPA’s analysis there were two product subcategories that had pass rates outside the range mentioned 361 
above: 362 
- The Online 2 transaction product bin has an abnormally high pass rate because most of the products in 363 
this bin exclusively implement SSDs which are the most efficient transaction focused device technology 364 
currently available in the storage market. The proposed level aims to reduce inefficient Online 2 365 
transaction systems which are dependent solely on using HDDs, while allowing passage for products 366 
making use of hybrid devices and/or SSDs.  367 
- EPA had very little data for products in the Online 3 streaming product bin. These data showed low 368 
performance compared to the streaming efficiency in the Online 2 and Online 4 categories. Without an 369 
explanation for this deviation, EPA is proposing to hold the active state requirement consistent across all 370 
three streaming subcategories at 4.0 MiBS/watt, but welcomes any stakeholder feedback that can explain 371 
why Online 3 products would be expected to operate less efficiently than similar Online 2 and Online 4 372 
products.  373 
Finally, EPA has provided guidance specifying that only one of the two sequential workload test 374 
requirements must be met for systems optimized for streaming workloads. EPA investigated combining 375 
the two sequential tests into a single streaming metric, but found that an insufficient number of products 376 
excelled in both workload tests.  377 
3.5 Energy Efficiency Feature Requirements 378 
3.5.1 To certify for ENERGY STAR, a storage product must contain the following feature, 379 
implemented as specified: 380 
i. Adaptive Active Cooling: Primary components of a storage product must utilize adaptive 381 
cooling technologies that reduce the energy consumed by the cooling technology in 382 
proportion to the current cooling needs to the storage product. (e.g., reduction of variable 383 
speed fan or blower speeds at lower ambient air temperature). This requirement is not 384 
applicable to devices that employ passive cooling. 385 
3.5.2 A storage product shall make available to the end user configurable / selectable features listed 386 
in Table 4 in quantities greater than or equal to those listed in Table 5. 387 
Table 4: Recognized COM Features 389 
Feature Verification Requirement 
COM: Thin Provisioning SNIA verification test 
COM: Data Deduplication SNIA verification test 
COM: Compression SNIA verification test 
COM: Delta Snapshots SNIA verification test 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 11 of 16 
Table 5: COM Requirements for Online 2, 3, and 4 Systems 391 
Storage Product 
Category 
Minimum number of COMs required to be 
made available 
Online 2 1 
Online 3 2 
Online 4 3 
Note: Based on stakeholder feedback from the Discussion Guide, EPA is proposing to increase the 392 
number of COMs required to be made available in Table 5 above, increasing by 1 for the Online 2 and 3 393 
categories, and by 2 for the Online 4 category.  394 
EPA has not removed thin provisioning from the COMs list in Table 4, as stakeholders provided example 395 
of Online 2 products which may not have it available. Maintaining thin provisions as an option for COMs 396 
should provide products with sufficient flexibility to meet the new COMs requirements.  397 
3.6 Information Reporting Requirements 398 
3.6.1 Active and Idle State Efficiency Disclosure: To certify for ENERGY STAR, all active and idle 399 
state test results based on workload tests listed in Table 6 or Table 7 shall be reported: 400 
Table 6: Required Workload Tests for all Block I/O Configurations 401 
Workload Test 
Hot Band 
Random Read 
Random Write 
Sequential Read 
Sequential Write 
Ready Idle3 
Table 7: Required Workload Tests for all File I/O Configurations 402 
Workload Test 
DATABASE 
SW Build 
Ready Idle3 
3.6.2 Workload Weighting Requirements: The weighted percentages shown in Table 8 or Table 9 403 
shall be used to calculate the appropriate Optimal Configuration point for a given storage 404 
product. 405 
3 SNIA defined workload tests in Table 6, Table 7, and through the rest of this document can be found in the “SNIA EmeraldTM Power Efficiency Measurement Specification” Version 3.0.3. Further detail may be found at www.snia.org/green. 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 12 of 16 
Table 8: Workload Weighting Requirements for all Block I/O Systems 407 
Workload Test Transaction Optimization 
Streaming 
Optimization Capacity Optimization 
Hot Band 100% 0% 0% 
Sequential Read 0% 50% 0% 
Sequential Write 0% 50% 0% 
Ready Idle 0% 0% 100% 
Example: To optimize for a streaming workload, manufacturers should identify a system configuration 409 
and storage device count where the weighted sum (per Table 7) of the Sequential Read and Sequential 410 
Write results are maximized. The resulting storage device count should be used as the streaming 411 
optimization point for ENERGY STAR testing and certification. The same weighting of the sums should 412 
also be used for subsequent certification measurements (e.g. determining optional flexible or mixed 413 
certification ranges). 414 
Table 9: Workload Weighting Requirements for all File I/O Systems 416 
Workload Test Transaction Optimization 
Streaming 
Optimization 
Composite Optimization 
DATABASE 50% 0% 0% 
SW Build 0% 0% 100% 
VDA 0% 100% 0% 
VDI 50% 0% 0% 
  417 
3.6.3 Testing Data Requirements for all Scale-up Storage Products:: The following test data is 418 
required for each configuration submitted for certification as ENERGY STAR: 419 
i. The manufacturer must choose a workload type for testing from 1.I.2. 420 
ii. The manufacturer must choose a single hard disk storage device, or combination of hard disk 421 
storage devices which result in the highest work/watt for that workload type. If no hard disk 422 
storage device is offered for the product, then the manufacturer shall select the most efficient 423 
single type or combination of solid state storage devices to represent the optimal 424 
configuration.  425 
iii. For the chosen workload type, physical data for all measurements listed in Table 6 or Table 7 426 
shall be submitted for a manufacturer determined Optimal Configuration point Additionally: 427 
iv. To certify additional workload types, repeat the above starting at 3.5.3.i for a different 428 
workload. 429 
v. The following rules apply to all testing above: 430 
(a) Verification testing of COM features (Table 4) specified by the storage product shall be 431 
executed at least once using storage devices of the vender’s choice.  Once verified there 432 
is no requirement to re-execute the COM verification testing procedure with different 433 
storage devices. 434 
(b) As noted in 1.I.3, a product family may not be based solely on Capacity workload 435 
Optimized Configurations.  Every storage device submitted for certification under 436 
Capacity Optimized Configurations must also include one or more Transaction workload 437 
Optimized Configuration(s) and/or Streaming workload Optimized Configuration(s) using 438 
the same storage device or combination of storage devices.  A Capacity workload 439 
Optimized Configuration may only be submitted as an addition to one (or more) of the 440 
other optimizations. 441 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 13 of 16 
Note: EPA has made significant revisions and simplification to the Test Data Requirement section above. 442 
These include: 443 
- Specifying that all optimal configurations submitted for certification should use either a manufacturer 444 
selected combination of spinning HDDs to maximize the efficiency (work/watt) of the workload under test 445 
OR the most efficient solid state storage offered for the product for the workload type being certified. 446 
Manufacturers shall only test with SSDs if the product is not sold with HDDs.  447 
- Removing existing guidance on fixed and flexible certification ranges and they are no longer relevant in 448 
Draft 1. 449 
- Removing guidance related to submitted modeled data for certification, as that option has been removed 450 
in Draft 1, based in part on discussions with manufacturers who found the modeling accuracy 451 
requirements too stringent to allow the use of modelers for certification purposes.  452 
3.6.4 Testing Data Requirements for all Scale-out Storage Products: The following test data is 453 
required for each configuration submitted for certification as ENERGY STAR: 454 
i. All testing and data requirements of Sections 3.5.3 shall be followed. 455 
ii. When testing, the smallest marketed quantity of storage controllers / nodes shall be tested. 456 
iii. Additional systems with a larger quantity of storage controllers may be optionally submitted. 457 
3.6.5 Data for display on the ENERGY STAR website shall be submitted for each ENERGY STAR 458 
certified storage product or storage product family. 459 
i. Whenever possible, Partners should also provide a hyperlink to a more detailed power 460 
calculator on their website that purchasers can use to understand power and performance 461 
data for specific configurations within the product family. 462 
3.6.6 The following information will be displayed on the ENERGY STAR website:  463 
i. Product model name, model number, and SKU or other configuration identification number; 464 
ii. A list of important product characteristics, including; 465 
(a) System configuration and tested I/O type; 466 
(b) Storage controller details (e.g. model name and number); 467 
(c) Software configuration and transfer protocols used in testing; 468 
(d) Storage controller power supply information; 469 
(e) Storage device drawer power supply information; 470 
(f) Storage devices used per optimization points; 471 
(g) Input power and environmental characteristics during testing; 472 
(h) System power optimization capabilities; 473 
(i) Inlet air temperature and power consumption reporting capabilities. 474 
iii. A list of optimal configurations of certified product families;  and disclosure of the time period 475 
used for data averaging.  476 
iv. A list of power management and other power saving features available and enabled by 477 
default; 478 
v. Specified thermal measurements conducted during testing;  479 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 14 of 16 
vi. For product families, a list of certified storage products within the family; and 480 
vii. Energy Efficiency Performance data (performance/watt) for required active and idle state test 481 
reporting specified in Table 10 or Table 11 below: 482 
Table 10: Active and Idle State Efficiency Block I/O Test Results Displayed  483 
Workload Test Transaction Optimization 
Streaming 
Optimization 
Capacity 
Optimization 
Hot Band Yes No No 
Random Read Yes No No 
Random Write Yes No No 
Sequential Read No Yes No 
Sequential Write No Yes No  
Ready Idle Yes Yes Yes 
Table 11: Active and Idle State Efficiency File I/O Test Results Displayed  485 
Workload Test Transaction Optimization 
Streaming 
Optimization 
Composite Optimization 
DATABASE Yes No No 
SW Build No No Yes 
VDA No Yes No 
VDI Yes No No 
Ready Idle Yes Yes Yes 
3.6.7 The following test information shall be submitted as part of the certification process, but will not 487 
be displayed on the ENERGY STAR website: 488 
i. Discrete power and performance data for all tested configurations; 489 
Note: EPA has removed obsolete references to minimum and maximum configurations, as well as the 491 
previous requirement in Section 3.6.7 to submit response time measurement data for all tested 492 
configurations. EPA intends to collect the discrete power and performance data for all tested configuration 493 
in Version 2.0, but will not collect response time measurements.  494 
3.7 Storage Product Family Variation Allowances 495 
Note: Based on the rationale EPA provided in the discussion guide, along with positive stakeholder 496 
feedback on that proposal, EPA has removed the Storage Product Family Variation Allowances section 497 
from the specification. With greater product family flexibility with only Optimal Configuration point testing 498 
in Draft 1, the previous variation allowances are no longer needed. 499 
3.8 Standard Performance Data Measurement and Output Requirements 500 
3.8.1 Data Elements: Online 3 and Online 4 storage products shall be capable of measuring and 501 
reporting the following data elements at the storage product level: 502 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 15 of 16 
i.     Input Power, in watts. Input power measurements must be reported with accuracy within 503 
±5% of the actual value for measurements greater than 200 W, through the full range of 504 
operation. For measurements less than or equal to 200 W, the accuracy must be less than 505 
or equal to 10 W multiplied by the number of installed PSUs; and 506 
ii.     Inlet Air Temperature (optional), in degrees Celsius, with accuracy of ± 2°C. 507 
3.8.2 Reporting Implementation:  508 
i.     Data shall be made available in a published or user-accessible format that is readable by 509 
third-party, non-proprietary management systems; 510 
ii.     Data shall be made available to end users and third-party management systems over a 511 
standard network connection;  512 
iii. Data shall be made available via embedded components or add-in devices that are 513 
packaged with the storage product (e.g., a service processor, embedded power or thermal 514 
meter or other out-of-band technology, or pre-installed OS); 515 
iv. When an open and universally available data collection and reporting standard becomes 516 
available, manufacturers should incorporate the universal standard into their products.  517 
3.8.3 Sampling Requirements:  518 
i.     Input power: Input power measurements must be sampled internally to the storage product 519 
at a rate of greater than or equal to 1 measurement per contiguous 10 second period.  520 
ii.     Inlet air temperature: Inlet air temperature measurements must be sampled internally to the 521 
storage product at a rate of greater than or equal to 1 measurement every 10 seconds. 522 
iii. Timestamping: Systems that implement time stamping of environmental data shall sample 523 
internally to the storage product data at a rate of greater than or equal to 1 measurement 524 
every 30 seconds. 525 
iv. Management Software: All sampled measurements shall be made available to external 526 
management software either via an on-demand pull method, or via a coordinated push 527 
method.  In either case the system’s management software is responsible for establishing 528 
the data delivery time scale while the storage product is responsible to assuring data 529 
delivered meets the above sampling and currency requirements. 530 
3.8.4 Documentation Requirements: The following information shall be included in the data submission: 531 
i.     Guaranteed accuracy levels for power and optional temperature measurements, and  532 
ii.     The time period used for data averaging (if present). 533 
Note: As discussed towards the end of Version 1.0 development, EPA is proposing the following two 534 
changes to Section 3.8: 535 
- Stated that all Online 3 and 4 products shall provide both input power and inlet air temperature 536 
measurements in Draft 1. Inlet air temperature reporting will no longer be optional.  537 
- Removed the option to use iPDUs to satisfy the Data Elements requirement, therefore requiring 538 
embedded components in the storage product to report this data as is required in the ENERGY STAR 539 
programs for Computer Servers and Large Network Equipment.  540 
ENERGY STAR Program Requirements for Data Center Storage – Eligibility Criteria Page 16 of 16 
4 TESTING 541 
4.1 Test Methods 542 
4.1.1 Test methods identified in Table 12 shall be used for purposes of evaluating active and idle 543 
state storage product energy efficiency. 544 
Table 12: Test Methods for ENERGY STAR Certification 545 
Product Type Test Method 
All ENERGY STAR Test Method for Data Center Storage Equipment, Rev. April 2019. 
Note: EPA anticipates the potential adoption of SNIA’s new Emerald V4 specification at a later date, but 546 
cannot reference it until it is sufficiently far along in development that no further revisions will be made. 547 
When Emerald V4 reaches this status, EPA intends to update the ENERGY STAR Data Center Storage 548 
test method, along with the Emerald references above in this specification, to reference the new Emerald 549 
V4 specification.  550 
4.2 Number of Units Required for Testing 552 
4.2.1 Representative Models shall be selected for testing per the following requirements: 553 
i. For certification of an individual product model, a product configuration equivalent to that 554 
which is intended to be marketed and labeled as ENERGY STAR is considered the 555 
Representative Model; 556 
ii. For certification of a product family one or more Optimization Configurations shall be tested 557 
and submitted.  Within the family covered by one or more Optimal Configurations, 558 
manufacturers continue to be held accountable for any efficiency claims made about their 559 
products, including those not tested or for which data was not reported; 560 
5 EFFECTIVE DATE 561 
5.1.1 Effective Date: The Version 2.0 ENERGY STAR Data Center Storage specification shall take 562 
effect on TBD. To certify for ENERGY STAR, a product model shall meet the ENERGY STAR 563 
specification in effect on its date of manufacture. The date of manufacture is specific to each 564 
unit and is the date on which a unit is considered to be completely assembled. 565 
5.1.2 Future Specification Revisions: EPA reserves the right to change this specification should 566 
technological and/or market changes affect its usefulness to consumers, industry, or the 567 
environment. In keeping with current policy, revisions to the specification are arrived at through 568 
stakeholder discussions. In the event of a specification revision, please note that the ENERGY 569 
STAR certification is not automatically granted for the life of a product model. 570 
6 CONSIDERATIONS FOR FUTURE REVISIONS 571 
TBD 572 