ISO/IEC 24091:2019

Information technology — Power efficiency measurement specification for data center storage

This document describes a standardized method to assess the energy efficiency of commercial storage products in both active and idle states of operation. A taxonomy is defined that classifies storage products in terms of operational profiles and supported features. Test definition and execution rules for measuring the power efficiency of each taxonomy category are described; these include test sequence, test configuration, instrumentation, benchmark driver, IO profiles, measurement interval, and metric stability assessment. Qualitative heuristic tests are defined to verify the existence of several capacity optimization methods. Resulting power efficiency metrics are defined as ratios of idle capacity or active operations during a selected stable measurement interval to the average measured power.

Titre manque

General Information

• Status: Published
• Publication Date: 21-Nov-2019
• ICS: 35.020 - Information technology (IT) in general
• Technical Committee: ISO/IEC JTC 1 - Information technology
• Drafting Committee: ISO/IEC JTC 1 - Information technology
• Current Stage: 9093 - International Standard confirmed
• Start Date: 10-May-2025
• Completion Date: 14-Feb-2026

Overview

ISO/IEC 24091:2019 - Information technology - Power efficiency measurement specification for data center storage - defines a standardized method to measure the power efficiency of commercial storage systems in data centers. Published as an ISO/IEC standard (adopted from SNIA Emerald™ Power Efficiency Measurement Specification v3.0.3), the document provides a taxonomy for classifying storage products, prescribes test definition and execution rules, and defines power-efficiency metrics for both active and idle operation.

Key topics and technical requirements

• Taxonomy and classifications
  • Standardized categories for storage products (e.g., Online, Near‑Online, Removable Media Library, Virtual Media Library) and rules for assigning operational profiles and feature sets.
• Test definition and execution rules
  • Detailed prescriptions for test sequence, test configuration, instrumentation, benchmark drivers, IO profiles, measurement intervals, and metric stability assessment.
• Instrumentation and benchmarks
  • Guidance on power/environmental meters, use of benchmark drivers (e.g., file/block IO drivers), and recommended workload profiles for conditioning and active phases.
• Capacity optimization verification
  • Qualitative heuristic tests to verify presence of capacity optimization methods (COMs) and characterization of space‑consuming practices.
• Metrics and stability
  • Primary metrics expressed as ratios of idle capacity or active operations during a selected stable measurement interval to average measured power (i.e., operations-per-watt or capacity-per-watt during stable intervals). Procedures for assessing metric stability and processing measurement data are included.
• Disclosure and reporting
  • Requirements for product identification, test characterization, and disclosure of test metrics and product-under-test descriptions to support objective comparison.

Practical applications

• Product benchmarking and R&D - Vendors use the standard to validate and optimize storage power behavior and to compare design choices.
• Procurement and TCO analysis - Data center operators and procurement teams apply standardized metrics to compare storage candidates on energy cost and total cost of ownership.
• Sustainability and reporting - Corporate sustainability teams leverage consistent power-efficiency data for energy footprint reduction and regulatory or voluntary reporting.
• Test labs and certification - Independent test labs implement the specified measurement procedures to provide repeatable, auditable efficiency results.

Who should use this standard

• Storage product manufacturers and design engineers
• Data center architects and operators
• Procurement specialists and IT financial planners
• Sustainability officers and energy-efficiency auditors
• Test laboratories and standards bodies

Related standards and references

• SNIA Emerald Power Efficiency Measurement Specification (origin of the PAS submission)
• Other ISO/IEC IT measurement and reporting standards (see ISO/IEC directives for related work)

Keywords: ISO/IEC 24091:2019, power efficiency, data center storage, storage power efficiency, taxonomy, test procedures, capacity optimization, metrics.

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 24091
First edition
2019-11
Information technology — Power
efficiency measurement specification
for data center storage
Reference number
©
ISO/IEC 2019
© ISO/IEC 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2019 – All rights reserved

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical activity.
ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of document should be noted (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. Details
of any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents) or the IEC list of patent
declarations received (see http://patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the World
Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT)
see www.iso.org/iso/foreword.html.
This document was prepared by SNIA (as SNIA Emerald™ Power Efficiency Measurement Specification
V3.0.3) and drafted in accordance with its editorial rules. It was adopted, under the JTC 1 PAS procedure,
by Joint Technical Committee ISO/IEC JTC 1, Information technology.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
© ISO/IEC 2019 – All rights reserved iii

Contents
1 Introduction . vii
2 Scope . 1
2.1 Abstract . 1
2.2 Introduction . 1
2.3 Current Revision . 1
2.4 Purpose . 1
2.5 Disclaimer . 2
3 Normative References . 3
4 Definitions, Symbols, Abbreviations, and Conventions . 4
4.1 Overview . 4
4.2 Definitions . 4
4.3 Symbols and Abbreviated Terms . 9
4.4 Expression of Provisions . 9
4.5 Conventions . 10
5 Taxonomy . 11
5.1 Introduction . 11
5.2 Taxonomy Categories . 12
5.3 Taxonomy Classifications . 12
5.4 Taxonomy Rules . 12
5.5 Online Category . 13
5.6 Near-Online Category . 15
5.7 Removable Media Library Category . 15
5.8 Virtual Media Library Category . 16
6 Capacity Optimization . 17
6.1 Introduction . 17
6.2 Space Consuming Practices . 17
6.3 COMs Characterized . 17
7 Test Definition and Execution Rules . 18
7.1 Overview . 18
7.2 General Requirements and Definitions . 18
7.3 Block Access Online and Near-Online Tests . 30
7.4 File Access Online and Near-Online Active Test . 33
7.5 Block and File Access Ready Idle Test . 37
7.6 Block and File Access Capacity Optimization Test . 37
7.7 Removable Media Library Testing . 42
7.8 Virtual Media Library Testing . 46
iv
© ISO/IEC 2019 – All rights reserved

8 Metrics . 50
8.1 Taxonomy Considerations . 50
8.2 Block Access Primary Metrics . 50
8.3 File Access Primary Metrics . 50
8.4 Power Efficiency Metric for Online and Near-Online Systems. 50
8.5 Power Efficiency Metric for Removable Media Library Systems . 52
8.6 Storage Power Efficiency Metric for Virtual Media Library Systems . 52
8.7 Secondary Metrics . 52
9 Disclosure Requirements . 54
9.1 General. 54
9.2 Product Identification . 54
9.3 Test Metrics . 54
9.4 Test Characterization . 56
9.5 Product Under Test Description . 57
Annex A (Normative) Suggested Power and Environmental Meters . 59
A.1 Overview . 59
A.2 Alternate Meter Usage . 59
Annex B (Normative) Measurement Requirements . 60
B.1 Online and Near-Online Block Access Data Collection and Processing Requirements . 60
B.2 Removable and Virtual Media Library Block Access Data Collection and Processing
Requirements . 60
B.3 Online and Near-Online File Access Data Collection and Processing Requirements . 60
Annex C (Normative) Stable Storage . 62
Annex D (Normative) Vdbench . 63
Annex E (Normative) Vdbench Test Scripts . 64 ®
Annex F (Normative) SPEC SFS 2014 Benchmark . 65
Annex G (Normative) File Access IO Load Driver Configuration File . 66 ®
Annex H (Informative) sFlow . 67
Annex I (Normative) COM Test Data Set Generator . 68
Annex J (Informative) gzip . 69
Bibliography . 70
© ISO/IEC 2019 – All rights reserved v

List of Tables, Figures and Equations
Table 1 – Normative References . 3
Table 2 – Taxonomy Overview . 11
Table 3 – Common Category Attributes . 12
Table 4 – Online Classifications . 14
Table 5 – Near-Online Classifications . 15
Table 6 – Removable Media Library Classifications . 16
Table 7 – Virtual Media Library Classifications . 16
Figure 1 - Sample Configuration Block Access . 19
Figure 2 - Sample Configuration File Access . 19
Table 8 – Example RAS Features . 20
Table 9 – Input Power Requirements (Products with Nameplate Rated Power ≤ 1 500 W) . 21
Table 10 – Input Power Requirements (Products with Nameplate Rated Power > 1 500 W) . 21
Table 11 – Power Meter Resolution . 22
Equation 7-1: Sequential Transfer Offset . 24
Figure 3 - Percentage of Address Hit vs. Cache Size . 24
Table 12 – Workloads within the Hot Band IO Profile . 25
Table 13 – IO Transfer Size within the Hot Band IO Profile for 512 Byte Native Devices . 25
Table 14 – IO Transfer Size within the Hot Band IO Profile for 4 KiB Native Devices . 26
Equation 7-2: Average Power . 27
Equation 7-3: Periodic Power Efficiency . 28
Equation 7-4: Least Squares Linear Fit Calculation . 29
Equation 7-5: Weighted Moving Average Calculation . 29
Table 15 – Pre-fill Test IO Profile . 30
Table 16 – Online and Near-Online Testing: Conditioning Test IO Profiles . 31
Table 17 – Online and Near-Online Testing: Active Test Phase IO Profiles . 32
Table 18 – Business Metrics for Workload Type . 35
Table 19 – Business Metrics for File Access Active Test Sequence . 36
Table 20 – Data Sets. 38
Table 21 – Drive Counts . 42
Table 22 – Removable Media Library Testing: Conditioning Test IO Profiles . 43
Table 23 – Removable Media Library Testing: Active Test Phase IO Profiles . 44
Equation 7-6: Sequential Transfer Offset . 45
Table 24 – Virtual Media Library Testing: Conditioning Test IO Profiles . 47
Table 25 – Virtual Media Library Testing: Active Test Phase IO Profiles . 48
Equation 7-7: Sequential Transfer Offset . 48
Equation 8-1: Power Efficiency, Ready Idle . 51
Equation 8-2: Power Efficiency, Active (Block Access) . 51
Equation 8-3: Power Efficiency, Active (File Access) . 51
Table B-1 Online and Near-Online Block Access Summary . 60
Table B-2 Removable and Virtual Media Library Summary . 60
Table B-3 Online and Near-Online File Access Summary . 61
vi
© ISO/IEC 2019 – All rights reserved

1 Introduction
There is a growing awareness of the environmental impact of IT equipment use. This impact takes several
forms: the energy expended in equipment manufacture and distribution, the impact of materials reclamation,
and the energy consumed in operation and cooling of the equipment. IT equipment users of all kinds now wish
to make their IT operations as energy efficient as possible. This new priority can be driven by one or more of
several requirements:
• Rising energy costs have made power and cooling expenses a more significant percentage of total cost of
ownership of server and storage equipment;
• Some data centers are physically unable to add more power and cooling load, which means that new
applications and data can only be brought on if old ones are retired or consolidated onto new, more
efficient configurations;
• Increased regulatory and societal pressures provide incentives for companies to lower their total energy
footprints. For many companies, IT is a significant portion of overall energy consumption, and corporate
Green goals can only be achieved by reducing IT’s energy needs or by making operations more efficient.
IT equipment users will seek advice on the most energy efficient approach to getting their work done. It is not
practical for customers to test a wide range of storage products and architectures for themselves. A more
effective approach is to create a collection of standard metrics that allow IT architects to objectively compare a
range of possible solutions. This objective, metric-based approach has a dual impact:
• Users can select the mode of storage usage that accomplishes their work objectives with the lowest
overall energy consumption;
• Companies will be driven to innovate and compete in the development of energy efficient products as
measured by the standard yardsticks.
© ISO/IEC 2019 – All rights reserved vii

2 Scope
2.1 Abstract
This document describes a standardized method to assess the energy efficiency of commercial
storage products in both active and idle states of operation. A taxonomy is defined that classifies
storage products in terms of operational profiles and supported features. Test definition and execution
rules for measuring the power efficiency of each taxonomy category are described; these include test
sequence, test configuration, instrumentation, benchmark driver, IO profiles, measurement interval,
and metric stability assessment. Qualitative heuristic tests are defined to verify the existence of
several capacity optimization methods. Resulting power efficiency metrics are defined as ratios of idle
capacity or active operations during a selected stable measurement interval to the average measured
power.
2.2 Introduction
This document defines methodologies and metrics for the evaluation of the related performance and
energy consumption of storage products in specific active and idle states.
Storage products and components are said to be in an “active” state when they are processing
externally initiated, application-level requests for data transfer between host(s) and the storage
product(s). For purposes of this document, idle is defined as “ready idle”, in which storage systems
and components are configured, powered up, connected to one or more hosts and capable of
satisfying externally initiated, application-level initiated IO requests within normal response time
constraints, but no such IO requests are being submitted.
2.3 Current Revision
This document addresses storage products supporting block or file data access. Block access and file
access refer to the type of service provided typically by Storage Area Network (SAN) and Network
Attached Storage (NAS) systems, respectively. It is not appropriate to use this document to ascertain
power efficiency for anything other than these two access modes. This document includes:
• A generalized taxonomy for storage products (clause 5);
• An assessment mechanism for software-based Capacity Optimization Methods (clause 6);
• Measurement and data collection guidelines for assessing the power efficiency of block- and file-
based storage products in both active and ready idle states (clause 7);
• Metrics describing storage product power efficiency (clause 8);
Power Efficiency
• Required disclosures for a test result published as a SNIA Emerald™
Measurement test result (clause 9 ).
2.4 Purpose
The purpose of a SNIA Emerald™ Power Efficiency Measurement is to provide a reproducible and
standardized assessment of the energy efficiency of commercial storage products in both active and
ready idle states.
1. Tested systems shall be comprised of commercially released products and components;
2. Tested systems shall employ settings, parameters, and configurations that would allow end-users
to achieve power efficiency levels equivalent to the published result;
3. All data published as an SNIA Emerald™ Power Efficiency Measurement test result shall be
gathered from test execution conducted according to this document;
SNIA Emerald™ is a trademark of the Storage Networking Industry Association. This information is
given for the convenience of users of this document and does not constitute an endorsement by ISO
of the product named.
© ISO/IEC 2019 – All rights reserved 1

4. Test execution shall complete in its entirety and without test failure or test error messages;
5. Software features which invoke, generate, or use software designed specifically for the test shall
not be used. Configuration options chosen for test execution shall be options that are generally
recommended for the customer;
6. Energy for powering the equipment shall be provided by the power mains that are being
monitored (not by an internal UPS).
A SNIA Emerald™ Power Efficiency Measurement shall be a good faith effort to accurately
characterize the power requirements of the tested system. The precise configuration used in a SNIA
Emerald™ Power Efficiency Measurement is left to the sponsor of a test. Any commercially released
components may be used, and a focus on new or emerging components or technologies is
encouraged.
2.5 Disclaimer
A SNIA Emerald™ Power Efficiency Measurement test result provides a high-level assessment of the
energy efficiency of the tested system in specific ready idle and active states. It is not an attempt to
precisely model or reproduce any specific installation.
Actual performance and energy consumption behavior is highly dependent upon precise workload,
environmental and usage parameters. While a SNIA Emerald™ Power Efficiency Measurement test
result is intended to provide a realistic and reproducible assessment of the relative power efficiency of
a system across a broad range of configurations and usage patterns, it cannot completely match the
precise needs of any one specific installation.
2 © ISO/IEC 2019 – All rights reserved

3 Normative References
The following documents are referred to in the text in a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
Table 1 lists these documents.
Table 1 – Normative References
Author/Owner Title Revision URL
ISO/IEC ISO/IEC Directives Part II Eighth edition, https://www.iso.org/directives-
2018 and-policies.html
© ISO/IEC 2019 – All rights reserved 3

4 Definitions, Symbols, Abbreviations, and Conventions
4.1 Overview
[2]
For the purposes of this document, the terms and definitions given in The SNIA Dictionary and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• ISO Online browsing platform: available at https://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
The terms and definitions defined in this document are based on those found in The SNIA
[2]
Dictionary . They have been extended, as needed, for use in this document. In cases where the
current definitions in the SNIA dictionary conflict with those presented in this document, the definitions
in this document shall apply.
4.2 Definitions
4.2.1
auto-tiering
policy-based system that automatically places and moves data across tiers to optimize performance
service levels, cost targets, and overall energy consumption
Note 1 to entry: Each storage tier may comprise different storage technologies, offering varying
performance, cost, and energy consumption characteristics.
4.2.2
cache
temporary storage used to transparently store data for expedited access to or from slower media, and
not directly addressable by end-user applications
4.2.3
capacity optimization method (COM)
subsystem, whether implemented in hardware or software, which reduces the consumption of space
required to store a data set
4.2.4
committed data
data that has been written to stable storage
4.2.5
compression
the process of encoding data to reduce its size
4.2.6
count-key-data (CKD)
disk data organization model in which the disk is assumed to consist of a fixed number of tracks, each
having a maximum data capacity
Note 1 to entry: The CKD architecture derives its name from the record format, which consists of a
field containing the number of bytes of data and a record address, an optional key field by which
particular records can be easily recognized, and the data itself.
© ISO/IEC 2019 – All rights reserved

4.2.7
data deduplication
replacement of multiple copies of data—at variable levels of granularity—with references to a shared
copy in order to save storage space and/or bandwidth
4.2.8
dedupable
property that a collection of data is said to possess if the needed storage capacity for the data is
reduced significantly by data deduplication
4.2.9
delta snapshot
type of point in time copy that preserves the state of data at an instant in time, by storing only those
blocks that are different from an already existing full copy of the data
4.2.10
direct-connected
storage designed to be under the control of a single host, or multiple hosts in a non-shared
environment
4.2.11
efficiency
ratio of useful work to the power required to do the work
4.2.12
file
abstract data object made up of a) an ordered sequence of data bytes stored on a disk or tape, b) a
symbolic name by which the object can be uniquely identified, and c) a set of properties, such as
ownership and access permissions that allow the object to be managed by a file system or backup
manager
4.2.13
file system
software component that imposes structure on the address space of one or more physical or virtual
disks so that applications may deal more conveniently with abstract named data objects of variable
size (files)
4.2.14
fixed block architecture (FBA)
model of disks in which storage space is organized as linear, dense address spaces of blocks of a
fixed size
Note 1 to entry: Fixed block architecture is the disk model on which SCSI is predicated.
4.2.15
fixed content addressable storage (FCAS)
storage optimized to manage content addressable data that is not expected to change during its
lifetime
© ISO/IEC 2019 – All rights reserved 5

4.2.16
formatted capacity
total number of bytes available to be written after a system or device has been formatted for use, e.g.,
by an object store, file system or block services manager
Note 1 to entry: Formatted capacity, also called usable capacity, is less than or equal to raw capacity.
It does not include areas set aside for system use, spares, RAID parity areas, checksum space, host-
or file system-level remapping, "right sizing" of disks, disk labeling and so on. However, it may include
areas that are normally reserved—such as snapshot set-asides—if they can alternatively be
configured for ordinary data storage by the storage administrator.
4.2.17
free space
amount of additional irreducible data that can be written to the product under test as configured
4.2.18
hot band
simulation of naturally occurring hot spots
4.2.19
hot spot
area of storage more frequently accessed across the addressable space
4.2.20
IO intensity
measure of the number of IOPS requested by a load generator
Note 1 to entry: IO intensity is phrased as a percentage of selected maximum IOPS level that
satisfies the timing requirement(s) for a taxonomy category.
4.2.21
irreducible data
data that is neither compressible nor dedupable
4.2.22
load generator
hardware and software environment executing the workload generator to drive the product under test
during measurements
4.2.23
Logical Unit (LU)
entity within a SCSI target that executes IO commands
4.2.24
Logical Unit Number (LUN)
synonym for logical unit
© ISO/IEC 2019 – All rights reserved

4.2.25
Maximum Time to First Data (MaxTTFD)
maximum time required to start receiving data from a storage system to satisfy a read request for
arbitrary data
4.2.26
network-connected
storage designed to be connected to a host via a network protocol (e.g., TCP/IP, IB, and FC)
4.2.27
non-disruptive serviceability
support for continued availability of data during all FRU service operations, including break/fix, code
patches, software/firmware upgrades, configuration changes, data migrations, and system expansion
Note 1 to entry: Service operations may impact performance, but shall not result in a loss of access.
4.2.28
parity RAID
collective term used to refer to Berkeley RAID Levels 3, 4, 5 and 6
4.2.29
permanent storage
data storage media which can retain data indefinitely without a power source
4.2.30
product under test
customer-orderable system or component that is the subject of a SNIA Emerald™ Power Efficiency
Measurement
4.2.31
raw capacity
sum of the raw, unformatted, uncompressed capacity of each storage device in the product under test
4.2.32
ready idle
operational state in which a system is capable of satisfying an arbitrary IO request within the response
time and MaxTTFD constraints of its selected taxonomy category, but no user-initiated IO requests
are being submitted to the system. In the ready idle state, background I/O activity, autonomously
initiated by the solution under test, may take place
4.2.33
sequential read
IO load consisting of consecutively issued read requests to logically adjacent data
4.2.34
sequential write
IO load consisting of consecutively issued write requests to logically adjacent data
© ISO/IEC 2019 – All rights reserved 7

4.2.35
Single Point of Failure (SPOF)
one component or path in a system, the failure of which would make the system inoperable or data
inaccessible
4.2.36
SNIA Emerald™ Power Efficiency Measurement
test performed according to this document
4.2.37
SNIA Emerald™ Power Efficiency Measurement test result
result of a test performed according to this document
4.2.38
solution under test
All hardware and software components that are exercised during a test to verify functional behavior or
determine performance characteristics, including all of the hardware and software components
involved in a test
Note 1 to entry: It includes the physical and virtual components of the load generator, storage media,
and the entire data path between the load generator and the storage media.
4.2.39
stable storage
storage that retains its content over power failures
Note 1 to entry: See Annex C.
4.2.40
storage controller
device for handling storage requests that includes a processor or sequencer programmed to
autonomously process a substantial portion of IO requests directed to storage devices
4.2.41
storage device
collective term for disk drives, solid state drives and modules, tape cartridges, and any other
mechanisms providing non-volatile data storage
Note 1 to entry: This definition is specifically intended to exclude aggregating storage elements such
as RAID array subsystems, robotic tape libraries, filers, and file servers. Also excluded are storage
devices which are not directly accessible by end-user application programs, and are instead
employed as a form of internal cache.
4.2.42
storage protection
any combination of hardware and software (e.g., RAID, NVRAM, disk sparing and background disk
scrubbing or media scan) that assures that all IO operations will be preserved in the event of power
loss or storage device failure
8 © ISO/IEC 2019 – All rights reserved

4.2.43
system crash
hardware or software failure which causes data to no longer be available, at least temporarily, and
which requires a reboot of one or more hardware components and/or re-initialization of one or more
software components in order for data access to be restored
4.2.44
test sponsor
individual, company, or agent that performs a test according to this document
4.2.45
thin provisioning
technology that allocates the physical capacity of a volume or file system as applications write data,
rather than pre-allocating all the physical capacity at the time of provisioning
4.2.46
virtual drive
removable media storage device (e.g., tape drive) that is emulated using other storage devices
4.2.47
workload generator
software used in the load generator to drive the product under test during measurement
4.3 Symbols and Abbreviated Terms
CKD Count-Key-Data
COM Capacity Optimization Method
FBA Fixed Block Architecture
FCAS Fixed Content Addressable Storage
FRU Field-Replaceable Unit
IT Information Technology
LU Logical Unit
LUN Logical Unit Number
MAID Massive Array of Idle Disks
MaxTTFD Maximum Time to First Data
NVRAM Non-Volatile Random Access Memory
RAS Reliability, Availability, and Serviceability
SCSI Small Computer System Interface
SNIA Storage Networking Industry Association
SPOF Single Point of Failure
UPS Uninterruptible Power Supply
4.4 Expression of Provisions
This document uses the verbal forms for expressions of provisions as defined by ISO/IEC Directives
Part 2 (Eighth edition, 2018). These verbal forms include shall, shall not, should, should not, may,
may not, can, cannot, and must.
© ISO/IEC 2019 – All rights reserved 9

4.5 Conventions
Certain words and terms used in this document have a specific meaning beyond their normal English
meaning. These words and terms are defined either in subclause 4.2 or in the text where they first
appear.
Storage capacities are represented in base-10. IO transfer sizes and offsets are represented in base-
2.
The associated units and abbreviations used in this document are:
• A kilobyte (KB) is equal to 10 B.
• A megabyte (MB) is equal to 10 B.
• A gigabyte (GB) is equal to 10 B.
• A terabyte (TB) is equal to 10 B.
• A petabyte (PB) is equal to 10 B.
• An exabyte (EB) is equal to 10 B.
• A kibibyte (KiB) is equal to 2 B.
• A mebibyte (MiB) is equal to 2 B.
• A gibibyte (GiB) is equal to 2 B.
• A tebibyte (TiB) is equal to 2 B.
• A pebibyte (PiB) is equal to 2 B.
• An exbibyte (EiB) is equal to 2 B.
© ISO/IEC 2019 – All rights reserved

5 Taxonomy
5.1 Introduction
This clause defines a market taxonomy that classifies storage products or subsystems in terms of
operational profile and supported features.
While this taxonomy is broad and defines a framework for products that range from consumer
solutions to enterprise installations, it is not intended to address all storage devices. For example, this
taxonomy does not address storage devices that rely on a Universal Serial Bus (USB) connection for
their power.
Further, while this document includes definitions for its entire taxonomy, it does not include testing
methodologies for the entire taxonomy. Both individual sections of the taxonomy (e.g., Near-Online-1)
and broader and more general groups of sections are not addressed beyond taxonomy definition in
this document. Their cells in Table 2 are shaded to make it clear that this omission in intentional.
Table 2 – Taxonomy Overview
Level Category
Online Near-Online Removable Media Library Virtual
(see (see 5.6) (see 5.7) Media
5.5) Library
(see
5.8)
Consumer/ Online Near-Online 1 Removable 1 Virtual
a
Component 1 1
Low-end Online Near-Online 2 Removable 2 Virtual
2 2
Online Near-Online 3 Removable 3 Virtual
3 3
Mid-range
Online
High-end Online Near-Online 5 Removable 5 Virtual
5 5
Mainframe Online Near-Online 6 Removable 6 Virtual
6 6
a
Entries in this level of taxonomy include both consumer products and data-center
components (e.g., stand-alone tape drives)
© ISO/IEC 2019 – All rights reserved 11

5.2 Taxonomy Categories
5.2.1 General
Taxonomy categories define broad market segments that can be used to group products that share
common functionality or performance requirements, and within which meaningful product comparison
can be undertaken. This document defines four broad taxonomy categories (summarized in Table 2):
• Online, defined in subclause 5.5;
• Near-Online, defined in subclause 5.6;
• Removable Media Library, defined in subclause 5.7;
• Virtual Media Library, defined in subclause 5.8.
Within a taxonomy category, a specific model or release of a product will support different feature
sets, whether focused on capacity, reliability, performance, functionality, or another differentiator.
Feature and functionality differences within a category are addressed with attributes. Each taxonomy
category defines a set of attributes that are common to all products within the category.
5.2.2 Category Attributes
Where a taxonomy category requires a specific, fixed setting or range for a given attribute, that setting
is summarized in Table 3 to assist a test sponsor in initial category selection. The full set of attributes
for each category is provided in subclauses 5.5 through 5.8.
Table 3 – Common Category Attributes
Attribute Category
Online Near- Removable Virtual Media
Online Media Library
Library
Access Pattern Random/ Random/ Sequential Sequential
Sequential Sequential
MaxTTFD (t) t < 80 ms t > 80 ms t > 80 ms t < 80 ms
t < 5 min
The attribute Consumer/Component refers to either
• Any of a wide array of manufactured goods which are purchased primarily for personal, family
and/or household purposes;
• A data-center component (e.g., a stand-alone tape drive or an individual hard disk drive) that is a
part of a data-center storage product.
5.3 Taxonomy Classifications
Classifications define combinations of settings or values for the attributes within a category.
5.4 Taxonomy Rules
A product shall satisfy all the attributes for its designated category and designated classification. If a
product satisfies the attributes of multiple classifications, the product may be considered to be in any
or all of these classifications. In cases where storage devices within a product fall within more than
one category or classification, the product shall be considered a member of the category and
classification whose requirements can be met by all of its storage devices.
Maximum Supported Configuration bounds the number of storage devices that the product is capable
of supporting.
© ISO/IEC 2019 – All rights reserved

A product shall be considered to be of a taxonomy category and classification if, in the Classification
Table for the category (Table 4, Table 5. Table 6, or Table 7):
1. The product has each of the features and functionalities listed as required or described in a
table entry;
2. The product has no feature or functionality listed as prohibited.
Note1: The presence or absence of attributes label as Optional has no impact on the category and
classification of a product.
Note 2: The nature of features and functionalities listed as Not Specified is not material to the
categorization of a product.
Note 3: Based on these rules, it is possible that a product is considered to be of multiple taxonomy
categories and/or multiple taxonomy classifications of a category.
5.5 Online Category
This category defines the features and functionalities for an online, random-access storage product.
Products in this profile may provide any combination of block, file, or object interfaces. Table 4 defines
the requirements for the taxonomy classifications defined in this category.
© ISO/IEC 2019 – All rights reserved 13

Table 4 – Online Classifications
Classification
Attribute
Online 1 Online 2 Online 3 Online 4 Online 5 Online 6
Random/ Random/ Random/ Random/ Random/ Random/
Access Pattern
Sequential Sequential Sequential Sequential Sequential Sequential
MaxTTFD (t) t < 80 ms t < 80 ms t < 80 ms t < 80 ms t < 80 ms t < 80 ms
Direct-
Not connected to Network- Network- Network- Network-
Connectivity
Specified single or connected connected connected connected
multiple hosts
Consumer/
Yes No No No No No
Component
Integrated
Storage Optional Optional Required Required Required Required
Controller
Storage
Optional Optional Required Required Required Required
Protection
No SPOF Optional Optional Optional Required Required Required
Optional, Optional,
Stable storage unless unless
Required Required Required Required
support Required Required by
by protocol protocol
Non-Disruptive
Optional Optional Optional Optional Required Required
Serviceability
FBA/CKD
Optional Optional Optional Optional Optional Required
Support
Maximum
Supported ≥ 1 ≥ 4 ≥ 12 > 100 > 400 > 400
a
Configuration
a
Maximum Supp
...