1. IBM Systems and Technology August 2011
Thought Leadership White Paper
Driving down power consumption
with the IBM XIV Storage System
From architecture to components, storage that’s designed to be green

2. 2 Driving down power consumption with the IBM XIV Storage System
Executive summary This paper illustrates how XIV storage architecture is
In recent decades, as organizations have dramatically expanded designed to be green and eco-friendly. Equally important,
their data centers, corporate IT energy demands and costs have it shows how the system can reduce power consumption by
risen in lockstep. Data center energy consumption is growing at more than 65 percent compared to comparable storage systems.
about 12 percent a year—and is expected to double in the next
five years.1 And data centers can be inefficient energy users. Energy costs and data volumes spur need
The U.S. Department of Energy estimates that most data for efficiency
centers can readily achieve 20 - 40 percent savings in energy The IT revolution has been accompanied by a dramatic rate of
consumption—and that aggressive measures can achieve better data center growth. The proliferation of data centers has been so
than 50 percent savings.1 Meanwhile, enterprise data is growing striking, in fact, that it is estimated that data centers alone now
at up to 50 percent a year,2 and storage capacity shipments are consume more than 2 percent of electric power in the US3 and
growing rapidly to meet that demand. With storage equipment 0.5 percent of electricity globally.4 Furthermore, as shown in
showing a high annual growth rate for energy demand, enter- Figure 1, the US Environmental Protection Agency (EPA)
prise storage has become a prime driver of data center energy estimated that data center energy consumption was to have
consumption. doubled between 2006 - 2011.5
These facts, along with increasing electricity costs, mandate the
important role for corporate IT of curbing an organization’s
power and cooling costs. Energy efficiency as a result has Figure 1: US data center electricity
become a key consideration in evaluating storage systems. consumption, 2000-2011
Annual electricity use (billion kWh/year)
The architectural rigidity of traditional storage systems, Historical Energy use
energy use projections
however, tends to result in high energy use. The need to accom-
modate future capacity, for example, often necessitates the
acquisition of more capacity and hardware than an organization
requires at the time of purchase. Ultimately, this over-capacity
can lead to higher power costs.
The IBM® XIV® Storage System is a high-end storage system,
designed to optimize the utilization of storage capacity while
providing consistent high performance. The many “green”
characteristics of the XIV system are designed to help companies
dramatically lower power consumption and energy costs while
meeting business needs. The amount of electricity used in data centers is on a steep increase,
prompting the need to enhance the efficiency of IT hardware such as data
storage systems.5

3. IBM Systems and Technology 3
Today, CIOs and IT management understand that keeping Complicating matters, most traditional storage systems consume
energy costs in check is an important component of their jobs. significant amounts of energy due to architectural limitations.
This energy imperative is particularly challenging given that Particularly challenging from an energy efficiency standpoint,
they must grapple with two near certainties of doing business the design of most traditional systems does not focus on opti-
today: the continued growth of their organization’s data capacity mizing capacity utilization. Consequently, companies typically
needs and an expected increase of 50 percent in electricity costs purchase more hardware than they need, powering and cooling
through 2035.6 orphaned or unused capacity. This results in higher power costs.
In light of increases in data volumes, rising energy costs and Today’s situation compels IT vendors and customers to face a
rising energy consumption—and their occurrence in a challeng- stark reality and address a formidable challenge: IT hardware in
ing business environment—using energy more efficiently makes general and storage equipment in particular must be designed
simple business sense. Energy-efficient companies can reduce with energy efficiency in mind. At the same time, performance
business risk, lower electricity bills, reduce carbon emissions and and reliability must continuously improve.
demonstrate environmental responsibility.
IBM has demonstrated its ongoing commitment to fusing
The role of storage in rising energy use technology with sustainability and the environment, among
and cost other activities, by launching Project Big Green and becoming a
The high growth rate in data center electricity consumption is member on the board of the Green Grid to promote green data
due in no small part to continuously growing demand for enter- centers. IBM’s Smarter Planet initiative focuses on optimizing
prise storage, making it increasingly clear that companies must the use of instrumented, interconnected and intelligent IT and
explore new approaches to maximize energy efficiency. Meeting business capabilities worldwide. Designed to be green to the
growing storage needs by simply adding another rack is, there- core, the XIV Storage System also embodies IBM’s commitment
fore, no longer the answer. Dense drives, reduced footprints and to the environment. Its benefits are two-fold: users can save
innovative advanced functions—all are required to meet today’s more than 65 percent on power and cooling costs and harness
demand for energy efficient storage. the power of high-end enterprise storage that delivers high
performance and reliability.

4. 4 Driving down power consumption with the IBM XIV Storage System
Architecture
IBM: Helping build a greener world The overriding principle for achieving an energy efficient
storage system is to optimize storage capacity utilization, thus
IBM is on the forefront of creating more energy efficient minimizing the amount of hardware necessary to provide usable
data centers, launching Project Big Green and leading the
storage capacity. The direct result of capacity optimization is
way as a board member of the Green Grid, both of which
lower energy costs.
are dedicated to promoting greener data centers. Other
energy-related activities include EPA Energy Star-compliant
servers and storage, carbon footprint consulting and Minimizing the hardware footprint required to deliver the
environmental information management. necessary usable capacity can be achieved through architecture
design considerations including:
A recognized leader for its work in sustainability, IBM has
received many awards and widespread recognition for its
G Eliminating orphaned space: Over time, 9 to 15 percent of
environmental efforts including:
most storage systems become unusable and “orphaned” for
G 2010: Two Most Valuable Pollution Prevention Awards from various reasons.7 Eliminating this phenomenon can immedi-
the National Pollution Prevention Roundtable ately reclaim a large amount of storage for use.
G 2010: Ranked #1 on Global 100 of Newsweek magazine’s G Providing thin provisioning: By defining virtual volumes
“Green Rankings”
of high capacity and using thin provisioning to map those
G 2009/08: Ranked #1 IDG/Computerworld’s annual Top
volumes to less physical space, storage administrators can pur-
Green-IT vendors ranking
chase the capacity they need today, not an estimated capacity
they might need in the future. Storage may be added in the
future on a just-in-time basis.
Creating the ultimate green storage G Utilizing differential backups: With differential backups,
only data that has changed is backed up. Conventional full
system
backup processes store volumes in their entirety, even if data
Imagine that a designer was tasked with creating a high-end
has not changed or there is no actual data in the volumes.
enterprise storage system with two primary goals: energy
efficiency and high performance. How would the designer
Experience shows that organizations can significantly reduce the
achieve these ostensibly opposed goals?
amount of storage overhead by integrating the above features,
leading to significant cost savings in power and cooling costs.
Conceptually, the storage system designer needs to optimize
storage capacity utilization. There are two elements with
which this may be achieved: system architecture and system
components. The resulting design concept would probably
look like this:

5. IBM Systems and Technology 5
Components
As for the physical components that make up the energy efficient
system, the design can take one of two paths: developing propri- “ IBM XIV storage is giving us greater power
etary, unique components optimized for a storage system or uti- densities, reducing the environmental and
lizing off-the-shelf commodity components. In terms of energy
efficiency as well as performance, commodity components are
overall operational cost of delivering the
the hands down winner. This is due to the following advantages: same amount of storage.”
G Leveraging advances in energy efficiency: Disk drive and
—Managed service provider, U.S.
processor companies are continuously improving the energy
efficiency of their products. When designing a system, it
makes sense to capitalize on these advances as they are released
on the market. Currently, very high density disks are the drives Letting the numbers do the talking
of choice for efficiency. In the future, new technologies that Before presenting the IBM XIV system design and architecture
provide higher energy efficiency can be integrated into the in detail, it would be useful to examine how its design affects
system. bottom line energy costs. The following sections contrast the
G Providing higher performance: Just as efficiency is improv- XIV system’s energy consumption to that of two comparable sys-
ing, disk drive and processor companies are also enhancing the tems, the EMC Symmetrix DMX-4 and EMC Symmetrix
performance of their components. By utilizing off-the-shelf VMAX. The EMC systems are similar to XIV systems in terms
components, a system can benefit from the latest research of usable capacity, performance, availability and feature sets.
and development in component performance and energy Both EMC systems were compared to second generation and
efficiency. Gen3 configurations of the IBM XIV Storage System.
IBM has designed the XIV Storage System using the approach The XIV Storage System versus EMC Symmetrix DMX-4
described above. Combining the best of architecture and The first comparison places Gen3 and second generation config-
commodity components, XIV storage is a high-end, high urations of the IBM XIV system—each with a usable capacity
performance, energy efficient solution. When it comes to of 111 TB—against an EMC Symmetrix DMX-4 system with
energy efficiency, XIV’s value proposition is simple: IBM allows
companies to focus on their business at lower energy costs.

6. 6 Driving down power consumption with the IBM XIV Storage System
109 TB of usable capacity8. The XIV systems are based on 2 TB
SAS (Gen3) and 2 TB SATA (second generation) disk drives,
while the DMX-4 system uses 450 GB Fibre Channel drives. All “ We were pushing against the limits of our
three systems offer comparable performance and features. data center in terms of power and space. The
The results are eye-opening. The Gen3 and second generation
XIV system gave us back some much-needed
XIV systems consume 67.9 percent and 62.5 percent less power, headroom … [and] on the financial side, we
respectively, than the EMC DMX-4 system. save 50,000 Australian dollars a year in
electricity costs.”
Figure 2: IBM XIV vs. EMC Symmetrix DMX-4
—Government agency, Australia.
XIV Storage System versus EMC Symmetrix VMAX
In this comparison, Gen3 and second generation XIV systems—
each with a usable capacity of 222 TB—are benchmarked against
an EMC Symmetrix VMAX system with a usable capacity of
212 TB9. The XIV systems are based on 2 TB SAS for Gen3
and 2 TB SATA disk drives for second generation, while the
VMAX system uses 600 GB Fibre Channel drives.
In this case, the Gen3 and second generation configurations of
IBM XIV Gen 3 IBM XIV second generation EMC DMX-4
the XIV system use 34.5 percent and 23.4 percent less power,
kVA TB / kVA respectively, than the EMC VMAX system.

7. IBM Systems and Technology 7
Figure 3: IBM XIV vs. EMC Symmetrix VMAX
“ The XIV system uses 50 percent less power
than the previous SAN system.”
—City government agency, U.S.
Reclaimed orphaned capacity
One of the drawbacks of most enterprise storage systems is that,
over time, an average of 9 to 15 percent of capacity becomes lost
and unusable. The complexity of volume management, volume
striping for performance and the ever-changing nature of
IBM XIV Gen 3 IBM XIV second generation EMC VMAX applications in an enterprise environment lead to the presence of
idle storage chunks. Known as “orphaned” space, these chunks
kVA TB / kVA
can be reclaimed in traditional storage systems only through
tedious system restructuring, a process that can be more
expensive than buying additional storage.
The IBM XIV Storage System:
The XIV Storage System automates much of the storage
Green by design management process, rendering obsolete the common tasks of
The IBM XIV Storage System is green by design, not by after-
striping and migrating or reallocating resources. The system is
thought. Unlike most competing systems, the XIV Storage
kept at a balance that maximizes the performance of all volumes
System has been designed to optimize capacity utilization. The
and utilizes all disks evenly. Defining new volumes, resizing
following sections describe how optimization is achieved
existing volumes, adding more capacity and even phasing out old
through the combination of architecture and components
hardware are all handled seamlessly by the XIV system, without
specifically designed to lower energy costs.
administrative effort. The system is designed to ensure that no
space is lost, there are no hotspots and energy is not wasted on
unutilized, orphaned capacity.

8. 8 Driving down power consumption with the IBM XIV Storage System
Differential backups/snapshots Actual energy savings generated by thin provisioning depends on
The ability to create periodic backups of entire volumes is various factors. Among them are enterprise applications’ data
essential to any enterprise storage system. Backups are required growth rate and a company’s implementation standards. It is
to maintain regulatory compliance, access older data, and restore IBM’s experience that when measured over three years, the
data upon failure or human error. With traditional enterprise XIV system can save as much up to 45 percent on capacity
systems, however, backup and restore processes can be costly. compared to a similar system without thin provisioning. Once
again, lower capacity translates into lower energy consumption
Traditional backup processes involve writing full volumes of data and costs.
onto additional unused storage space. This includes copying
unused space that has never been written to and should not be
copied. XIV storage handles backup with differential backups
Figure 4: Capacity utilization
and snapshots, copying only the blocks of data that have actually
been written. It does not copy unwritten or “zero” data. In
contrast to legacy systems, which require higher rates of unused
space, the XIV approach greatly reduces the capacity, time and
cost necessary for backups. Implementations of XIV Storage
Systems, in fact, have experienced reductions in storage capacity
requirements as great as 15 to 30 percent, thus reducing energy
consumption.
Built-in thin provisioning
The XIV Storage System includes thin provisioning as a core
feature of its design, managed at the click of a button. Thin
provisioning provides the ability to define a system’s logical
capacity as larger than its physical capacity. This enables compa- Traditional Tier-1 system IBM XIV system
nies to defer physical capacity purchases and acquire physical Lost Full Thick Effective
capacity solely for the total space actually written rather than the space snapshots provisioning capacity
total space allocated. While it is true that most enterprise storage
solutions offer thin provisioning, in many systems this feature is
added to existing architectures, making it harder to manage and Thick to thin allocation
of limited scope. With the XIV system, thin provisioning is Organizations choosing to switch from a legacy storage system
incorporated from the beginning as a fully integrated system to XIV storage can seamlessly benefit from the system’s thin
component. allocation features. When a thickly provisioned volume is
migrated from a legacy system, the XIV system’s thin provision-
ing mechanism will not allocate any unused space. Instead, it can

9. IBM Systems and Technology 9
shrink existing volumes upon migration by copying only con- Automatic load balancing and self-healing
sumed blocks of storage. With XIV storage, capacity is not used System load balancing and self-healing enable XIV storage to
until it is required. This results in higher capacity utilization and provide Tier-1, enterprise-level performance while using fewer
lower energy requirements. drives. By using fewer drives for a given capacity, XIV storage
consumes less electricity and can provide better performance
Instant space reclamation than that of traditional systems through the use unique
The XIV Storage System offers the capability of reclaiming data algorithms and data distribution.
that was previously in use but is now out of use. When applica-
tions are logically formatting areas of the volume, the formatted Single-tier architecture
capacity is reassigned to another volume. The system performs Most IT organizations use practices such as information lifecycle
space reclamation automatically and offers easy management management (ILM) to reduce costs. These efforts involve multi-
tools for leveraging this capability to the fullest. Instant space tiering, however, which adds a substantial degree of complexity
reclamation allows XIV users to optimize capacity utilization. It and cost to system management. A multitier storage solution
can reduce costs by enabling supporting applications to instantly typically involves a number of different architectures, each
regain unused file system space in thin-provisioned volumes. requiring a different level of expertise to manage. Moving the
data between tiers requires effort and planning and involves
The XIV Storage System supports Symantec’s Storage hardware and operating expenses for each tier. As each environ-
Foundation Thin Reclamation API. The Symantec API inter- ment grows, equipment must be added to one tier or another.
locks with the XIV system to instantly detect unused space and Since this growth is typically unpredictable, acquisitions are
automatically and immediately reassign the space to the general often not cost efficient.
storage pool as unused capacity. This is a tight integration point
with thin-provisioning-aware Veritas File System (VxFS) by The single-tier XIV architecture can eliminate the complexity
Symantec. It ultimately enables companies to leverage the thin- and cost of migrating data from tier to tier. It also can reduce the
provisioning-awareness of the XIV Storage System to attain complexity of maintaining different architectures for different
higher savings in storage utilization with Symantec file systems. tiers of storage. From the standpoint of energy efficiency, it
enables scaling of components—including capacity, interfaces,
More information on space reclamation is available in the cache, CPU power and internal bandwidth—on the same plat-
IBM XIV thin reclamation white paper. form. As a result, less hardware is required with the XIV system
to achieve the same usable capacity. This combination provides
the ability to dramatically cut energy costs.

10. 10 Driving down power consumption with the IBM XIV Storage System
Components advantage: Very high XIV power: Designed for high-end
density hard drives enterprise storage
The XIV Storage System can minimize costs and provide Just as its storage architecture can directly reduce energy needs
exceptional flexibility by treating hardware as an interchangeable and expenditures, the XIV system’s electric power design can
commodity. Based on off-the-shelf hardware components, lower costs in an indirect yet significant manner. Designed for
XIV storage is designed to integrate the latest disks, modules, enterprise-grade storage, the XIV system includes the following
interconnects and other components, enabling organizations to features to protect against electricity provisioning problems:
capitalize on market advances in capacity, cost and energy
efficiency while meeting their dynamic performance and budget G Power feed redundancy: XIV storage plugs into two
requirements. different power grids, assuring redundancy in the case of
power outages.
XIV storage utilizes very high density hard drives to drive down G Automatic transfer switch (ATS): The ATS provides seam-
energy costs. Leveraging the energy and capacity advances of less failover from primary to a secondary or tertiary source and
off-the-shelf high density drives enables the XIV system to pro- back. This is especially important for switching to a backup
vide more storage with significantly lower energy consumption power source for the provisioning of temporary electric power.
per capacity unit. Future growth in drive capacities can result in G UPS system: The UPS system sustains system power
corresponding savings in energy use and cost. redundancy in the event that one power grid fails.
G Power monitoring: The XIV system user interface includes
power monitoring capabilities in which each power compo-
nent and element can be monitored separately. Administrators
“ One of the targets that we have … is to save can also define alarms, warnings and alerts in case of power
energy and floor space … In the consolidated issues, spikes and other issues.
space we are being more efficient in a smaller
footprint. Right now in the computer center
we are running in one rack what we used to
have in five different racks.”
—Insurance company, Puerto Rico

11. IBM Systems and Technology 11
industry leading energy efficiency. The XIV Storage System has
shown that combining innovative architecture with commodity
components can reduce storage energy costs by more than 65
percent when compared to competing systems.
As data growth rates and energy prices increase, companies must
identify IT solutions that reduce energy consumption without
compromising performance, features or reliability. Designed to
be green, the XIV Storage System is such a solution. It can play
an important role in helping your company achieve its energy-
efficiency requirements.
For more information
To learn more about IBM XIV Storage Systems, please contact
your IBM marketing representative or IBM Business Partner or
visit: ibm.com/systems/storage/disk/xiv
A graphical interface simplifies management of system components with
point-and-click checks, including for power status. Additionally, financing solutions from IBM Global Financing
can enable effective cash management, protection from technol-
ogy obsolescence, improved total cost of ownership and return
Conclusion on investment. Also, our Global Asset Recovery Services help
The XIV Storage System is a high-end data storage system
address environmental concerns with new, more energy-efficient
offering numerous advanced features and documented benefits
solutions. For more information on IBM Global Financing, visit:
to enterprise organizations. One of the primary benefits is its
ibm.com/financing

12. © Copyright IBM Corporation 2011
IBM Systems and Technology Group
1
Scheihing, Paul, U.S. Department of Energy, DOE Data
Route 100
Center Energy Efficiency Program: Save Energy Now, April 2009,
Somers, NY 10589
http://www1.eere.energy.gov/industry/datacenters/pdfs/
U.S.A.
doe_data_centers_presentation.pdf
Produced in the United States of America
2
Wexler, Joanie, Gauging the volume: What to expect in data
August 2011
storage and network traffic growth, Network World, January 3, 2011,
All Rights Reserved
http://www.networkworld.com/news/2011/010311-outlook-volume.html?
page=1 IBM, the IBM logo, ibm.com and XIV are trademarks of International
Business Machines Corporation in the United States, other countries or
3
Dr. Steven Chu, National Data Center Power Reduction Incentive
both. If these and other IBM trademarked terms are marked on their first
Program, 2009, http://datacenterpulse.org/downloads/
occurrence in this information with a trademark symbol (® or ™), these
DCP09_National_DC_Energy_Program-FINAL.pdf
symbols indicate U.S. registered or common law trademarks owned by
4
Jonathan G. Koomey, Worldwide Electricity Used in Data Centers, 2008, IBM at the time this information was published. Such trademarks may also
http://iopscience.iop.org/1748-9326/3/3/034008 be registered or common law trademarks in other countries. A current list of
IBM trademarks is available on the web at “Copyright and trademark
5
U.S. Environmental Protection Agency, Energy Star Program, Report information” at ibm.com/legal/copytrade.shtml
to Congress on Server and Data Center Energy Efficiency Public Law
109-431, http://www.energystar.gov/ia/partners/prod_development/ Other company, product or service names may be trademarks or service
downloads/EPA_Datacenter_Report_Congress_Final1.pdf marks of others.
6
U.S. Energy Information Administration, Annual Energy Outlook 2011: This document could include technical inaccuracies or typographical errors.
With Projections to 2035, Washington, DC, April 2011, page 133, IBM may make changes, improvements or alterations to the products,
http://www.eia.gov/forecasts/aeo/pdf/0383(2011).pdf programs and services described in this document, including termination of
such products, programs and services, at any time and without notice. Any
7
Harwood, Tom, Stop Buying Storage Best Practices, Symantec, statements regarding IBM’s future direction and intent are subject to change
page 11, http://www.symantec.com/connect/sites/default/files/ or withdrawal without notice, and represent goals and objectives only. The
20016958-2_GA_WP_Stop_Buying_Storage_Best_Practices_ information contained in this document is current as of the initial date of
CCS_and_VSF_03-09.pdf Figures cited combine 7 to 10 percent “claimed” publication only and is subject to change without notice. IBM shall have no
storage assets and 2 to 5 percent “unassigned” assets. responsibility to update such information.
8
EMC power consumption figures are based on data that appear in the EMC IBM is not responsible for the performance or interoperability of any
Symmetrix DMX-4 specification sheet, http://www.emc.com/collateral/ non-IBM products discussed herein. Performance data for IBM and
hardware/specification-sheet/c1166-dmx4-ss.pdf Specifications for the non-IBM products and services contained in this document was derived
XIV Storage System are based on information at the following web page: under specific operating and environmental conditions. The actual results
http://www.ibm.com/systems/storage/disk/xiv/specifications.html obtained by any party implementing such products or services will depend
on a large number of factors specific to such party’s operating environment
9
EMC power consumption figures are based on data that appear in the EMC and may vary significantly. IBM makes no representation that these results
Symmetrix VMAX specification sheet, http://www.emc.com/collateral/ can be expected or obtained in any implementation of any such products or
hardware/specification-sheet/h6176-symmetrix-vmax-storage-system.pdf services.
Specifications for the XIV Storage System are based on information at the
following web page: http://www.ibm.com/systems/storage/disk/xiv/ The information in this document is provided “as-is” without any warranty,
specifications.html either expressed or implied.
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