IBM Systems and TechnologyThought Leadership White Paper

August 2011

Driving down power consumptionwith the IBM XIV Storage SystemFrom architecture to components, storage that’s designed to be green

2 Driving down power consumption with the IBM XIV Storage System

Executive summaryIn recent decades, as organizations have dramatically expandedtheir data centers, corporate IT energy demands and costs haverisen in lockstep. Data center energy consumption is growing atabout 12 percent a year—and is expected to double in the nextfive years.1 And data centers can be inefficient energy users. The U.S. Department of Energy estimates that most data centers can readily achieve 20 - 40 percent savings in energyconsumption—and that aggressive measures can achieve betterthan 50 percent savings.1 Meanwhile, enterprise data is growingat up to 50 percent a year,2 and storage capacity shipments aregrowing rapidly to meet that demand. With storage equipmentshowing a high annual growth rate for energy demand, enter-prise storage has become a prime driver of data center energyconsumption.

These facts, along with increasing electricity costs, mandate theimportant role for corporate IT of curbing an organization’spower and cooling costs. Energy efficiency as a result hasbecome a key consideration in evaluating storage systems.

The architectural rigidity of traditional storage systems, 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 organizationrequires at the time of purchase. Ultimately, this over-capacitycan lead to higher power costs.

The IBM® XIV® Storage System is a high-end storage system,designed to optimize the utilization of storage capacity whileproviding consistent high performance. The many “green” characteristics of the XIV system are designed to help companiesdramatically lower power consumption and energy costs whilemeeting business needs.

This paper illustrates how XIV storage architecture is designed to be green and eco-friendly. Equally important, it shows how the system can reduce power consumption by more than 65 percent compared to comparable storage systems.

Energy costs and data volumes spur needfor efficiencyThe IT revolution has been accompanied by a dramatic rate ofdata center growth. The proliferation of data centers has been sostriking, in fact, that it is estimated that data centers alone nowconsume more than 2 percent of electric power in the US3 and0.5 percent of electricity globally.4 Furthermore, as shown inFigure 1, the US Environmental Protection Agency (EPA) estimated that data center energy consumption was to have doubled between 2006 - 2011.5

Figure 1: US data center electricityconsumption, 2000-2011

Historicalenergy use

Energy useprojections

Annu

al e

lect

ricity

use

(billi

on k

Wh/

year

)

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 datastorage systems.5

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Today, CIOs and IT management understand that keepingenergy costs in check is an important component of their jobs.This energy imperative is particularly challenging given thatthey must grapple with two near certainties of doing businesstoday: the continued growth of their organization’s data capacityneeds and an expected increase of 50 percent in electricity coststhrough 2035.6

In light of increases in data volumes, rising energy costs and rising energy consumption—and their occurrence in a challeng-ing business environment—using energy more efficiently makessimple business sense. Energy-efficient companies can reducebusiness risk, lower electricity bills, reduce carbon emissions anddemonstrate environmental responsibility.

The role of storage in rising energy useand costThe high growth rate in data center electricity consumption isdue in no small part to continuously growing demand for enter-prise storage, making it increasingly clear that companies mustexplore new approaches to maximize energy efficiency. Meetinggrowing storage needs by simply adding another rack is, there-fore, no longer the answer. Dense drives, reduced footprints andinnovative advanced functions—all are required to meet today’sdemand for energy efficient storage.

Complicating matters, most traditional storage systems consumesignificant amounts of energy due to architectural limitations.Particularly challenging from an energy efficiency standpoint,the design of most traditional systems does not focus on opti-mizing capacity utilization. Consequently, companies typicallypurchase more hardware than they need, powering and coolingorphaned or unused capacity. This results in higher power costs.

Today’s situation compels IT vendors and customers to face astark reality and address a formidable challenge: IT hardware ingeneral and storage equipment in particular must be designedwith energy efficiency in mind. At the same time, performanceand reliability must continuously improve.

IBM has demonstrated its ongoing commitment to fusing technology with sustainability and the environment, amongother activities, by launching Project Big Green and becoming amember on the board of the Green Grid to promote green datacenters. IBM’s Smarter Planet initiative focuses on optimizingthe use of instrumented, interconnected and intelligent IT andbusiness capabilities worldwide. Designed to be green to thecore, the XIV Storage System also embodies IBM’s commitmentto the environment. Its benefits are two-fold: users can savemore than 65 percent on power and cooling costs and harnessthe power of high-end enterprise storage that delivers high performance and reliability.

4 Driving down power consumption with the IBM XIV Storage System

IBM: Helping build a greener world

IBM is on the forefront of creating more energy efficient data centers, launching Project Big Green and leading theway as a board member of the Green Grid, both of which are dedicated to promoting greener data centers. Otherenergy-related activities include EPA Energy Star-compliantservers and storage, carbon footprint consulting and environmental information management.

A recognized leader for its work in sustainability, IBM hasreceived many awards and widespread recognition for itsenvironmental efforts including:

! 2010: Two Most Valuable Pollution Prevention Awards fromthe National Pollution Prevention Roundtable

! 2010: Ranked #1 on Global 100 of Newsweek magazine’s“Green Rankings”

! 2009/08: Ranked #1 IDG/Computerworld’s annual TopGreen-IT vendors ranking

Creating the ultimate green storagesystemImagine that a designer was tasked with creating a high-endenterprise storage system with two primary goals: energy efficiency and high performance. How would the designerachieve these ostensibly opposed goals?

Conceptually, the storage system designer needs to optimizestorage capacity utilization. There are two elements with which this may be achieved: system architecture and systemcomponents. The resulting design concept would probably look like this:

ArchitectureThe overriding principle for achieving an energy efficient storage system is to optimize storage capacity utilization, thusminimizing the amount of hardware necessary to provide usablestorage capacity. The direct result of capacity optimization islower energy costs.

Minimizing the hardware footprint required to deliver the necessary usable capacity can be achieved through architecturedesign considerations including:

! Eliminating orphaned space: Over time, 9 to 15 percent ofmost storage systems become unusable and “orphaned” forvarious reasons.7 Eliminating this phenomenon can immedi-ately reclaim a large amount of storage for use.

! Providing thin provisioning: By defining virtual volumes of high capacity and using thin provisioning to map those volumes to less physical space, storage administrators can pur-chase the capacity they need today, not an estimated capacitythey might need in the future. Storage may be added in thefuture on a just-in-time basis.

! Utilizing differential backups: With differential backups,only data that has changed is backed up. Conventional fullbackup processes store volumes in their entirety, even if datahas not changed or there is no actual data in the volumes.

Experience shows that organizations can significantly reduce theamount of storage overhead by integrating the above features,leading to significant cost savings in power and cooling costs.

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ComponentsAs for the physical components that make up the energy efficientsystem, the design can take one of two paths: developing propri-etary, unique components optimized for a storage system or uti-lizing off-the-shelf commodity components. In terms of energyefficiency as well as performance, commodity components arethe hands down winner. This is due to the following advantages:

! Leveraging advances in energy efficiency: Disk drive andprocessor companies are continuously improving the energyefficiency of their products. When designing a system, itmakes sense to capitalize on these advances as they are releasedon the market. Currently, very high density disks are the drivesof choice for efficiency. In the future, new technologies thatprovide higher energy efficiency can be integrated into thesystem.

! Providing higher performance: Just as efficiency is improv-ing, disk drive and processor companies are also enhancing theperformance of their components. By utilizing off-the-shelfcomponents, a system can benefit from the latest research and development in component performance and energy efficiency.

IBM has designed the XIV Storage System using the approachdescribed above. Combining the best of architecture and commodity components, XIV storage is a high-end, high performance, energy efficient solution. When it comes to energy efficiency, XIV’s value proposition is simple: IBM allowscompanies to focus on their business at lower energy costs.

“ IBM XIV storage is giving us greater powerdensities, reducing the environmental andoverall operational cost of delivering thesame amount of storage.”

—Managed service provider, U.S.

Letting the numbers do the talkingBefore presenting the IBM XIV system design and architecturein detail, it would be useful to examine how its design affectsbottom line energy costs. The following sections contrast theXIV system’s energy consumption to that of two comparable sys-tems, the EMC Symmetrix DMX-4 and EMC SymmetrixVMAX. The EMC systems are similar to XIV systems in termsof usable capacity, performance, availability and feature sets.Both EMC systems were compared to second generation andGen3 configurations of the IBM XIV Storage System.

The XIV Storage System versus EMC Symmetrix DMX-4The first comparison places Gen3 and second generation config-urations of the IBM XIV system—each with a usable capacity of 111 TB—against an EMC Symmetrix DMX-4 system with

6 Driving down power consumption with the IBM XIV Storage System

109 TB of usable capacity8. The XIV systems are based on 2 TBSAS (Gen3) and 2 TB SATA (second generation) disk drives,while the DMX-4 system uses 450 GB Fibre Channel drives. Allthree systems offer comparable performance and features.

The results are eye-opening. The Gen3 and second generationXIV systems consume 67.9 percent and 62.5 percent less power,respectively, than the EMC DMX-4 system.

Figure 2: IBM XIV vs. EMC Symmetrix DMX-4

IBM XIV Gen 3 IBM XIV second generation EMC DMX-4

kVA TB / kVA

“We were pushing against the limits of ourdata center in terms of power and space. TheXIV system gave us back some much-neededheadroom … [and] on the financial side, wesave 50,000 Australian dollars a year inelectricity costs.”

—Government agency, Australia.

XIV Storage System versus EMC Symmetrix VMAXIn this comparison, Gen3 and second generation XIV systems—each with a usable capacity of 222 TB—are benchmarked againstan EMC Symmetrix VMAX system with a usable capacity of 212 TB9. The XIV systems are based on 2 TB SAS for Gen3and 2 TB SATA disk drives for second generation, while theVMAX system uses 600 GB Fibre Channel drives.

In this case, the Gen3 and second generation configurations ofthe XIV system use 34.5 percent and 23.4 percent less power,respectively, than the EMC VMAX system.

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Figure 3: IBM XIV vs. EMC Symmetrix VMAX

IBM XIV Gen 3 IBM XIV second generation EMC VMAX

kVA TB / kVA

The IBM XIV Storage System: Green by designThe IBM XIV Storage System is green by design, not by after-thought. Unlike most competing systems, the XIV StorageSystem has been designed to optimize capacity utilization. Thefollowing sections describe how optimization is achievedthrough the combination of architecture and components specifically designed to lower energy costs.

“The XIV system uses 50 percent less powerthan the previous SAN system.”

—City government agency, U.S.

Reclaimed orphaned capacityOne of the drawbacks of most enterprise storage systems is that,over time, an average of 9 to 15 percent of capacity becomes lostand unusable. The complexity of volume management, volumestriping for performance and the ever-changing nature of applications in an enterprise environment lead to the presence ofidle storage chunks. Known as “orphaned” space, these chunkscan be reclaimed in traditional storage systems only throughtedious system restructuring, a process that can be more expensive than buying additional storage.

The XIV Storage System automates much of the storage management process, rendering obsolete the common tasks ofstriping and migrating or reallocating resources. The system iskept at a balance that maximizes the performance of all volumesand utilizes all disks evenly. Defining new volumes, resizing existing volumes, adding more capacity and even phasing out oldhardware are all handled seamlessly by the XIV system, withoutadministrative effort. The system is designed to ensure that nospace is lost, there are no hotspots and energy is not wasted onunutilized, orphaned capacity.

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Differential backups/snapshotsThe ability to create periodic backups of entire volumes is essential to any enterprise storage system. Backups are requiredto maintain regulatory compliance, access older data, and restoredata upon failure or human error. With traditional enterprisesystems, however, backup and restore processes can be costly.

Traditional backup processes involve writing full volumes of dataonto additional unused storage space. This includes copyingunused space that has never been written to and should not becopied. XIV storage handles backup with differential backupsand snapshots, copying only the blocks of data that have actuallybeen written. It does not copy unwritten or “zero” data. In contrast to legacy systems, which require higher rates of unusedspace, the XIV approach greatly reduces the capacity, time andcost necessary for backups. Implementations of XIV StorageSystems, in fact, have experienced reductions in storage capacityrequirements as great as 15 to 30 percent, thus reducing energyconsumption.

Built-in thin provisioning The XIV Storage System includes thin provisioning as a corefeature of its design, managed at the click of a button. Thin provisioning provides the ability to define a system’s logicalcapacity as larger than its physical capacity. This enables compa-nies to defer physical capacity purchases and acquire physicalcapacity solely for the total space actually written rather than thetotal space allocated. While it is true that most enterprise storagesolutions offer thin provisioning, in many systems this feature isadded to existing architectures, making it harder to manage andof limited scope. With the XIV system, thin provisioning isincorporated from the beginning as a fully integrated systemcomponent.

Actual energy savings generated by thin provisioning depends onvarious factors. Among them are enterprise applications’ datagrowth rate and a company’s implementation standards. It isIBM’s experience that when measured over three years, the XIV system can save as much up to 45 percent on capacity compared to a similar system without thin provisioning. Onceagain, lower capacity translates into lower energy consumptionand costs.

Figure 4: Capacity utilization

Traditional Tier-1 system IBM XIV system

Lostspace

Fullsnapshots

Thickprovisioning

Effectivecapacity

Thick to thin allocationOrganizations choosing to switch from a legacy storage systemto XIV storage can seamlessly benefit from the system’s thinallocation features. When a thickly provisioned volume ismigrated from a legacy system, the XIV system’s thin provision-ing mechanism will not allocate any unused space. Instead, it can

9IBM Systems and Technology

shrink existing volumes upon migration by copying only con-sumed blocks of storage. With XIV storage, capacity is not useduntil it is required. This results in higher capacity utilization andlower energy requirements.

Instant space reclamationThe XIV Storage System offers the capability of reclaiming datathat was previously in use but is now out of use. When applica-tions are logically formatting areas of the volume, the formattedcapacity is reassigned to another volume. The system performsspace reclamation automatically and offers easy managementtools for leveraging this capability to the fullest. Instant spacereclamation allows XIV users to optimize capacity utilization. Itcan reduce costs by enabling supporting applications to instantlyregain unused file system space in thin-provisioned volumes.

The XIV Storage System supports Symantec’s StorageFoundation Thin Reclamation API. The Symantec API inter-locks with the XIV system to instantly detect unused space andautomatically and immediately reassign the space to the generalstorage pool as unused capacity. This is a tight integration pointwith thin-provisioning-aware Veritas File System (VxFS) bySymantec. It ultimately enables companies to leverage the thin-provisioning-awareness of the XIV Storage System to attainhigher savings in storage utilization with Symantec file systems.

More information on space reclamation is available in the IBM XIV thin reclamation white paper.

Automatic load balancing and self-healingSystem load balancing and self-healing enable XIV storage toprovide Tier-1, enterprise-level performance while using fewerdrives. By using fewer drives for a given capacity, XIV storageconsumes less electricity and can provide better performancethan that of traditional systems through the use unique algorithms and data distribution.

Single-tier architectureMost IT organizations use practices such as information lifecyclemanagement (ILM) to reduce costs. These efforts involve multi-tiering, however, which adds a substantial degree of complexityand cost to system management. A multitier storage solutiontypically involves a number of different architectures, eachrequiring a different level of expertise to manage. Moving thedata between tiers requires effort and planning and involveshardware and operating expenses for each tier. As each environ-ment grows, equipment must be added to one tier or another.Since this growth is typically unpredictable, acquisitions areoften not cost efficient.

The single-tier XIV architecture can eliminate the complexityand cost of migrating data from tier to tier. It also can reduce thecomplexity of maintaining different architectures for differenttiers of storage. From the standpoint of energy efficiency, itenables scaling of components—including capacity, interfaces,cache, CPU power and internal bandwidth—on the same plat-form. As a result, less hardware is required with the XIV systemto achieve the same usable capacity. This combination providesthe ability to dramatically cut energy costs.

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Components advantage: Very highdensity hard drivesThe XIV Storage System can minimize costs and provide exceptional flexibility by treating hardware as an interchangeablecommodity. Based on off-the-shelf hardware components, XIV storage is designed to integrate the latest disks, modules,interconnects and other components, enabling organizations tocapitalize on market advances in capacity, cost and energy efficiency while meeting their dynamic performance and budgetrequirements.

XIV storage utilizes very high density hard drives to drive downenergy costs. Leveraging the energy and capacity advances ofoff-the-shelf high density drives enables the XIV system to pro-vide more storage with significantly lower energy consumptionper capacity unit. Future growth in drive capacities can result incorresponding savings in energy use and cost.

“One of the targets that we have … is to saveenergy and floor space … In the consolidatedspace we are being more efficient in a smallerfootprint. Right now in the computer centerwe are running in one rack what we used tohave in five different racks.”

—Insurance company, Puerto Rico

XIV power: Designed for high-endenterprise storageJust as its storage architecture can directly reduce energy needsand expenditures, the XIV system’s electric power design canlower costs in an indirect yet significant manner. Designed forenterprise-grade storage, the XIV system includes the followingfeatures to protect against electricity provisioning problems:

! Power feed redundancy: XIV storage plugs into two different power grids, assuring redundancy in the case ofpower outages.

! Automatic transfer switch (ATS): The ATS provides seam-less failover from primary to a secondary or tertiary source andback. This is especially important for switching to a backuppower source for the provisioning of temporary electric power.

! UPS system: The UPS system sustains system power redundancy in the event that one power grid fails.

! Power monitoring: The XIV system user interface includespower monitoring capabilities in which each power compo-nent and element can be monitored separately. Administratorscan also define alarms, warnings and alerts in case of powerissues, spikes and other issues.

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A graphical interface simplifies management of system components withpoint-and-click checks, including for power status.

ConclusionThe XIV Storage System is a high-end data storage systemoffering numerous advanced features and documented benefitsto enterprise organizations. One of the primary benefits is its

industry leading energy efficiency. The XIV Storage System hasshown that combining innovative architecture with commoditycomponents can reduce storage energy costs by more than 65percent when compared to competing systems.

As data growth rates and energy prices increase, companies mustidentify IT solutions that reduce energy consumption withoutcompromising performance, features or reliability. Designed tobe green, the XIV Storage System is such a solution. It can playan important role in helping your company achieve its energy-efficiency requirements.

For more informationTo learn more about IBM XIV Storage Systems, please contactyour IBM marketing representative or IBM Business Partner orvisit: ibm.com/systems/storage/disk/xiv

Additionally, financing solutions from IBM Global Financingcan enable effective cash management, protection from technol-ogy obsolescence, improved total cost of ownership and returnon investment. Also, our Global Asset Recovery Services helpaddress environmental concerns with new, more energy-efficientsolutions. For more information on IBM Global Financing, visit:ibm.com/financing

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IBM, the IBM logo, ibm.com and XIV are trademarks of InternationalBusiness Machines Corporation in the United States, other countries orboth. If these and other IBM trademarked terms are marked on their firstoccurrence in this information with a trademark symbol (® or ™), thesesymbols indicate U.S. registered or common law trademarks owned by IBM at the time this information was published. Such trademarks may alsobe registered or common law trademarks in other countries. A current list ofIBM trademarks is available on the web at “Copyright and trademarkinformation” at ibm.com/legal/copytrade.shtml

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This document could include technical inaccuracies or typographical errors.IBM may make changes, improvements or alterations to the products,programs and services described in this document, including termination ofsuch products, programs and services, at any time and without notice. Anystatements regarding IBM’s future direction and intent are subject to changeor withdrawal without notice, and represent goals and objectives only. Theinformation contained in this document is current as of the initial date ofpublication only and is subject to change without notice. IBM shall have noresponsibility to update such information.

IBM is not responsible for the performance or interoperability of any non-IBM products discussed herein. Performance data for IBM and non-IBM products and services contained in this document was derivedunder specific operating and environmental conditions. The actual resultsobtained by any party implementing such products or services will dependon a large number of factors specific to such party’s operating environmentand may vary significantly. IBM makes no representation that these resultscan be expected or obtained in any implementation of any such products orservices.

The information in this document is provided “as-is” without any warranty,either expressed or implied.

1 Scheihing, Paul, U.S. Department of Energy, DOE Data Center Energy Efficiency Program: Save Energy Now, April 2009,http://www1.eere.energy.gov/industry/datacenters/pdfs/doe_data_centers_presentation.pdf

2 Wexler, Joanie, Gauging the volume: What to expect in data storage and network traffic growth, Network World, January 3, 2011,http://www.networkworld.com/news/2011/010311-outlook-volume.html?page=1

3 Dr. Steven Chu, National Data Center Power Reduction Incentive Program, 2009, http://datacenterpulse.org/downloads/DCP09_National_DC_Energy_Program-FINAL.pdf

4 Jonathan G. Koomey, Worldwide Electricity Used in Data Centers, 2008,http://iopscience.iop.org/1748-9326/3/3/034008

5 U.S. Environmental Protection Agency, Energy Star Program, Report to Congress on Server and Data Center Energy Efficiency Public Law 109-431, http://www.energystar.gov/ia/partners/prod_development/downloads/EPA_Datacenter_Report_Congress_Final1.pdf

6 U.S. Energy Information Administration, Annual Energy Outlook 2011:With Projections to 2035, Washington, DC, April 2011, page 133,http://www.eia.gov/forecasts/aeo/pdf/0383(2011).pdf

7 Harwood, Tom, Stop Buying Storage Best Practices, Symantec, page 11, http://www.symantec.com/connect/sites/default/files/20016958-2_GA_WP_Stop_Buying_Storage_Best_Practices_CCS_and_VSF_03-09.pdf Figures cited combine 7 to 10 percent “claimed”storage assets and 2 to 5 percent “unassigned” assets.

8 EMC power consumption figures are based on data that appear in the EMCSymmetrix DMX-4 specification sheet, http://www.emc.com/collateral/hardware/specification-sheet/c1166-dmx4-ss.pdf Specifications for the XIV Storage System are based on information at the following web page:http://www.ibm.com/systems/storage/disk/xiv/specifications.html

9 EMC power consumption figures are based on data that appear in the EMCSymmetrix VMAX specification sheet, http://www.emc.com/collateral/hardware/specification-sheet/h6176-symmetrix-vmax-storage-system.pdfSpecifications for the XIV Storage System are based on information at thefollowing web page: http://www.ibm.com/systems/storage/disk/xiv/specifications.html

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