1

Managing the information that drives the enterprise

STORAGEVol. 9 No. 2 April 2010

PrimaryStorageDishes UpDedupeData deduplication hasquickly become a keyingredient of manybackup systems and nowthe capacity-condensingbenefits of data reductionare ready for primarystorage. P. 13 ALSO INSIDE

5 Vendors put a spin on solid-state storage

22 Director-class switches unsnarl clogged networks

30 SRM tools: Do you need them now?

38 Disk-based backup on a roll

41 Tape use dips, but few have eliminated it

Storage April 2010

STORAGEsponsors | april 2010

2

RReeggiioonnaall SSoolluuttiioonn PPrroovviiddeerrss::

Storage April 2010

STORAGEinside | april 2010

3 Cover illustration by ENRICO VARRASSO

The Solid State of Storage Efficiency5 EDITORIAL Storage managers want to use their storage

systems more efficiently and vendors are finally forking over the tools to do it; but there may be a catch as vendors are faced with decreasing disk sales. by RICH CASTAGNA

Seeking Clarity in the Clouds8 STORWARS You’ll have to wade through the confusion

that cloud computing vendors have created, but you may find that there are advantages to both public and private cloud offerings. by TONY ASARO

Dedupe and Compression Cut Storage Down to Size13 Data reduction technologies like data deduplication and

compression have been well integrated into backup systems with impressive results. Now those benefits are available for primary storage data systems. Learn about the different primary storage data reduction technologies and find outwhich vendors have real products. by W. CURTIS PRESTON

SAN Consolidation With Director-Class Switches22 A single director-class switch can replace multiple smaller

switches while offering growth flexibility, high availability and a bevy of advanced features. We compare offerings from Brocade, Cisco and QLogic to illustrate the benefits of moving to a director-based storage network infrastructure. by DENNIS MARTIN

SRM Tools Struggle to Meet Today’s Demands30 At one time, storage resource management (SRM) applications

tried to be all things for all storage shops, with little success. Modern data storage environments require new tools and metrics, but the jury’s still out on whether storage management vendors can meet those needs. by ALAN RADDING

The Modernization of Backup: More Disk, Less Tape38 HOT SPOTS Results from ESG’s 2010 Data Protection Survey

show that the trend away from tape continues, with the economics of both deduplication, for disk-based backup, and cloud storage, for long-term retention, contributing to tape’s decline. by LAUREN WHITEHOUSE

Tape May be Teetering, but Still a Big Part of Backup Ops41 SNAPSHOT Tape no longer holds the place it once did in most

firms’ backup environments, but most storage shops still relyon it to some degree. Our Snapshot survey finds that while thevast majority of respondents use disk in backup, nearly 40%plan to buy tape gear this year. by RICH CASTAGNA

Vendor Resources42 Useful links from our advertisers.

Online data sets have different characteristics than backups, so delivering meaningful

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EFFECTIVE PRIMARY STORAGE OPTIMIZATION MEANS MORE THAN JUST DEDUPLICATION.

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Storage April 2010

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iT LOOKS LIKE data storage system vendors are in a bit of a bind these days.While the success of several high-tech housekeeping technologies won’tput the brakes on the seemingly nonstop cycle of IT purchasing more andmore storage hardware, it can sure slow it down considerably.

It could be the fallout from a couple of cruddy years economy-wise, orjust natural evolution, but more storage managers are looking for ways topare down the data they store to try to keep it close to manageable pro-portions. While most vendors responded with little more than lip service,3PAR shrewdly saw an opening for its pioneering thin provisioning technolo-gy that provides a no-nonsense approach to using already installed capacitymore efficiently. It wasn’t just a cool feature; it was a savvy move by astartup vendor that ultimately forced most other vendors to include thinprovisioning in their products.

With thin provisioning becoming well entrenched as a checkbox featurefor most storage arrays, data reduction in primary storage (that’s a mouthful,so let’s just call it DRIPS) is taking center stage. DRIPS presents another approach-avoidance situation for storage vendors. I’m sure most would like to avoid it and just sell more disk, but if they don’t roll out their ownapproaches to tweezing and squeezing primary storage data they’ll run therisk of being left in the dust by their competitors. Credit NetApp and start-ups (upstarts?) Storwize and Ocarina Networks for getting the DRIPS ballrolling, and now everyone will have to get into the game.

While we’re at it, let’s add automated storage tiering to the list. Led (or pushed) by Compellent, which didn’t invent the concept but certainlypumped some life into it, storage vendors are actually trying to help theircustomers put data in its place—even if that place is on cheap disk.

So storage vendors might be just a little staggered by this one-two-three punch that lets storage managers buy storage later when it getscheaper, buy less of it now or buy only inexpensive types of disk.

But storage vendors are a resourceful bunch and aren’t likely to take

Copyright 2010, TechTarget. No part of this publication may be transmitted or reproduced in any form, or by any means, without permission in writing from the publisher. For permissions or reprint information, please contact Mike Kelly, VP and Group Publisher (mkelly@techtarget.com).

editorial | rich castagna

The solid state of storage efficiency

Storage managers want to use their storage systems more efficiently and vendors are

finally forking over the tools to do it; but there may be a catch.

5

Storage April 20106

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STORAGE

this whole efficiency thing lying down. A number of them have alreadyseized on another hot storage technology—solid-state storage—to counterthe effects of possibly selling fewer storage systems and less-expensivedisks to fill them. Until it gets much, much cheaper, solid state only hasone role in the data center: handling the highest-performing apps in a com-pany’s portfolio. But array vendors are trying to tie solid state to automatedtiering and other good housekeeping practices.

In my mind, I find it hard to link tiering with solid-state storage, but I’veheard some pretty persuasive pitches that can make it seem only naturalthat you have solid state at the top of your tier and SATA below. And withautomatic tiering moving your data around based on how IOPS-hungry it isat the time, it’s logical to have the most ex-pensive, highest-performing storage as thetop tier. That all seems to make some senseon paper, unless the paper you’re writing onis your company’s check for a new array.

Any tiered storage arrangement has to havea top level of fast storage. But does it have tobe that fast? Yes, it does, according to pitches I’ve heard recently from storage systems vendors. They were pretty convincing, and it allalmost made sense until the price tag for thattop-tier solid-state storage was revealed. The connection between automatedtiering and solid-state storage seems contrived at best. It looks more likethose vendors are conceding some ground to the efficiency techs while try-ing to carve out some new (and very lucrative) turf somewhere else.

There’s no question that solid-state storage (even at its current astronom-ical price) has a place in many data centers, serving up data to applicationsthat need the kind of performance that only solid state offers. And right nowthere’s a tremendous amount of interest in solid state, but I believe that’smostly focused on the future of the technology when its price will be a lotless than 30 or 50 times that of spinning disk. Maybe one day solid statewill also be an efficiency story, but right now it’s just about pure speed. 2

Rich Castagna (rcastagna@storagemagazine.com) is editorial director of theStorage Media Group.

* Click here for a sneak peek at what’s coming up in the May 2010 issue.

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Storage April 20108

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iRECENTLY CONDUCTED a seminar in Seattle for a number of IT professionalsand when I mentioned the “cloud” there was a wave of negative reaction.They hated the term and thought that it was just a lot of hyperbole. Whenour industry latches onto buzzwords like “cloud” and gives them so muchairplay, there’s invariably a backlash from the user community. It createsconfusion and often winds up being counterproductive to vendors’ mar-keting efforts.

Adding to the confusion is that more thanone type of IT cloud exists. There are applica-tion clouds, like SalesForce.com and GoogleApps. These online applications are often re-ferred to as software as a service (SaaS), butthe “application cloud” moniker is beginning to stick. According to research firm IDC, appli-cation clouds already represent an $8.5 billionmarket, which impacts on-premises IT infra-structures. Applications that would otherwiselive within your company’s four walls are instead accessed over the cloud, and so theservers, network, storage, power, cooling andfloor space that would have been required on your shop floor are nowprovided by the application vendor.

There are also pure IT public clouds that provide compute resourcesand/or storage capacity, with new businesses like Dropbox and Twitterleveraging these services. We can expect IT professionals to use publicIT cloud services as a supplement to existing on-premises IT infrastruc-ture. For example, a high-tech startup I just spoke with is using bothAmazon Elastic Compute Cloud (EC2) and Simple Storage Service (S3) for test and development vs. building an in-house lab. Public IT cloudswill be used for research, testing, lower tier applications, secondarycopies of data, backup, archive storage and so on.

Public IT clouds won’t replace brick-and-mortar IT within the fore-seeable future. I’ve spoken to more than 200 IT professionals over thelast 12 months and none of them has a serious initiative to use publicIT clouds. But a shift is coming with the availability of more products

StorWars | tony asaro

Seeking clarity in the cloudsAfter you wade through the confusion that vendors

have created, you’ll find there are advantages to both public and private cloud offerings.

According toresearch firm IDC,application cloudsalready represent an$8.5 billion market,which impacts on-premises IT infrastructures.

Storage April 2010

and services that enable IT professionals to easily, cost effectively andsecurely use public IT cloud services.

Private IT clouds is another category that some people believe is justa new name for the same stuff we already have in the data center. Idisagree. Regardless of what we call this new “thing”—a true IT utilityor private IT cloud—it isn’t synonymous with what we have today in the data center, although many of the ingredients are the same.

The IT professionals I’ve spoken to about private IT clouds see it as therealization of IT as a utility within their own companies. It uses physicalIT infrastructure for greater economies of scale, which is what a utility isall about.

We’ve been talking about turning IT into a service utility for decades,so what’s changed in that time? The biggest thing has been server virtu-alization, which creates an n-to-1 virtual server-to-physical server ratio.Virtual LANs (VLANs) have done the same thing for networking. Addition-ally, some storage systems let you create virtual storage systems in asimilar fashion. We have advanced IT technology to enable multi-tenancyand create logical systems within physical ones. The virtualization of ITinfrastructure is relatively new and essential to enabling private IT clouds.

The critical pieces still missing for private IT clouds are the manage-ment, policy-based controls, reporting, analysis and “billing” systems forthe entire IT ecosystem holistically. This is what will elevate private ITclouds from being a disparate set of virtual and physical infrastructuresolutions to the new way we manage our data centers. But this is thehardest part to build because it requires core competencies that the infrastructure vendors don’t have. Additionally, you need to work with a wide range of products and vendors that may or may not cooperate.

Both public and private IT clouds are real and changing the land-scape, but nothing is binary. We don’t do things one way and thenswitch to another way overnight. It takes years, with progress occurringin steps. There are points of acceleration and, depending on the ease ofmaking the shift, the clarity of the value proposition and the support ofthe ecosystem, the time it takes to complete the transition can varyconsiderably. And as markets emerge, no one can predict how it will allplay out.

So what’s an IT professional to do? Do what you always do whenfaced with something new and emerging. The early adopters will leadthe way and some of them will make great choices while others makemistakes. Keep reading, researching and analyzing. You might want toeven dip your toe in the waters if the cost and risk is minimal. Set yourcynicism aside and try to understand how IT clouds can impact yourenvironment for the short term while you continue to evaluate thelong-term implications. 2

Tony Asaro is senior analyst and founder of Voices of IT (www.VoicesofIT.com).

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STORAGE

Whatever the Business Climate, We’ll Focus on Keeping You Covered

Hitachi is a registered trademark of Hitachi, Ltd., and/or its affiliates in the United States and other countries. Hitachi Data Systems is a registered trademark and service mark of Hitachi, Ltd., in the United States and other countries. All other trademarks, service marks and company names are properties of their respective owners. © Hitachi Data Systems Corporation 2009. All Rights Reserved.

Hitachi SolutionsOptimizing Business Resilience in Virtualized Environments www.hds.com

If optimizing and protecting your virtualized environments is your objective, Hitachi has the solution. Whether you want to improve data protection or to extend disaster recovery to additional data, Hitachi has the solutions your organization needs to optimize efficiency and resilience in both VMware and Microsoft® Hyper-V environments.

For more information on our solutions for business resilience in your virtualized environment, please visit:www.hds.com/solutions

Storage April 201011

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STORAGE

Vice President of EditorialMark Schlack

Editorial DirectorRich Castagna

Senior Managing EditorKim Hefner

Senior EditorEllen O’Brien

Creative DirectorMaureen Joyce

Editorial AssistantFrancesca Sales

Contributing EditorsTony AsaroJames Damoulakis Steve Duplessie Jacob Gsoedl

Site EditorEllen O’Brien

Senior News DirectorDave Raffo

Senior News WriterBeth Pariseau

Features WriterCarol Sliwa

Senior Managing EditorKim Hefner

Associate Site EditorChris Griffin

Site EditorSusan Troy

Site Editor Andrew Burton

Associate Site EditorHeather Darcy

Assistant Site EditorMegan Kellet

Features WriterTodd Erickson

Executive Editor andIndependent Backup ExpertW. Curtis Preston

TechTarget Conferences

Director of Editorial EventsLindsay Mullen

Editorial Events AssociateNicole Tierney

Storage magazine275 Grove Street Newton, MA 02466editor@storagemagazine.com

Subscriptions: www.SearchStorage.com

STORAGE

TechTarget Storage Media Group

What Storage ManagersAre Buying in 2010Twice a year, Storagemagazine/SearchStorage.comsurveys storage managersto see how they plan tospend their budgets and which technologies they’reconsidering for purchase.This is the eighth year ofour exclusive StoragePurchasing IntentionsSurvey, and we’ll analyzethe current survey resultsand compare them to pastdata to determine the stor-age buying trends that willemerge in 2010.

What’s New and What’s Coming in Disk Drive TechnologyOver the past few years,the capacity of SATA diskshas doubled and then dou-bled again. In addition tobuilding drives with higherand higher capacities, diskdrive manufacturers areadding features such asencryption and power con-servation. In this article,we look at the progress ofhard disk drive technologieswith an eye toward whatwe can expect in the nextyear or so.

Alternatives to RAIDWhile most shops still relyon venerable RAID technol-ogy to help protect theirdata, new technologies areemerging that forego theuse of traditional RAID.Although these new sys-tems often borrow fromRAID technology and tech-niques, they offer similarprotection without requiringRAID controllers or soft-ware. We describe howthese systems work, as well as their benefits andshortcomings compared to traditional RAID.

STORAGECOMING IN MAY

And don’t miss our monthly columns and commentary, or the results of our Snapshot reader survey.

In with the AND. Out with the OR. Choosing either lower IT cost or improved business performance is so last fiscal year. With NetApp’s uncompromising approach to enterprise storage solutions, you can now have both. To see how your business can benefit from storage efficiency without compromise, visit netapp.com/and.

© 2010 NetApp. All rights reserved. Specifications are subject to change without notice. NetApp, the NetApp logo, and Go further, faster are trademarks or registered trademarks of NetApp, Inc. in the United States and/or other countries. All other brands or products are trademarks or registered trademarks of their respective holders and should be treated as such.

uStorage April 201013

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Dedupe andcompression

cut storagedown to size

SE LESS DISK, save more electricity. What’s not to like? If you buy the rightproducts, you can pare down the disk capacity your data needs and maybeeven cut your electric bills by as much as 50%. That’s the promise of primarystorage data reduction, and while slashing utility costs is appealing, there’sstill plenty of skepticism about the claimed benefits of the technology.While there’s little dispute that this new class of products can reduce the amount of disk your primary storage uses, uncertainty remains aboutwhether the gains outweigh the challenges of primary storage data reduction.

Data reduction technologies like datadeduplication and compression havebeen well integrated into backupsystems with impressive results. Now those benefits are available for primary storage data systems.

By W. Curtis Preston

Storage April 2010

The key questions about primary storage data reduction include thefollowing:

• Why is it called “data reduction” rather than data deduplication?• Disk is cheap. Why bother adding new technologies to reduce the

size of the data it holds?• What are the different types of data reduction for primary storage?• How much disk space can actually be saved?

DATA REDUCTION DEFINED In backup environments, data deduplication is a recognized and appro-priate term for the technologies that eliminate redundancies in backupsets, but for primary storage, data reduction is a more accurate termbecause not all data reduction technologies use deduplication tech-niques. As an umbrella term, data reduction includes any technologythat reduces the footprint of your data on disk. There are three maintypes of data reduction in use today: compression, file-level deduplica-tion and sub-file-level deduplication.

Before we examine these different technologies—all of which wereused for backups before they were applied to primary storage—let’slook at how very different primary data storage is from backup datastorage. The main difference between primary storage and backups isthe expectation of the entity that’s storing or accessing the data. Back-ups are typically written in large batches by automated processes thatare very patient. These processes are accustomed to occasional slow-downs and unavailability of resources, and even have built-in technologiesto accommodate such things. Backups are rarely read, and when they

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STORAGE

PRIMARY STORAGE DATA REDUCTION VENDORS

VENDOR

EMC Corp.

Exar Corp.

GreenBytes Inc.

Microsoft Corp.

NetApp Inc.

Nexenta Systems Inc.

Ocarina Networks

Oracle-Sun

Storwize Inc.

PRODUCT

Celerra NS-120, NS-480, NS-960, NS-G8 Gateway

Hifn BitWackr B1605R

GB-X Series

Windows Storage Server 2008

Ontap operating system for FAS Filers

NexentaStor 3.0

ECOsystem and ECOvault

ZFS file system

STN Series appliances

TYPE OF DATA DEDUPLICATION

File-level

Sub-file-level

Sub-file-level

File-level

Sub-file-level

Sub-file-level

Sub-file-level

Sub-file-level

None

COMPRESSION

Yes

Yes

Yes

No

No

Yes

Yes

Yes

Yes

Storage April 2010

are, performance expectations are modest: Someone calls and requestsa file or database to be restored, and an administrator initiates therestore request. Unless the restore takes an abnormally long time, no one truly notices how long it took. Most people have adjusted theirexpectations so that they’re happy if the restore worked at all. (This issad, but unfortunately true.) This typical usage pattern of a disk-basedbackup system means you could slow down backups quite a bit with-out a lot of people noticing.

Primary storage is very different. Data is written to primary storagethroughout the day and it’s typically written directly by real people whoare entering numbers into spreadsheets, updating databases, storingdocuments or editing multimedia files. These activities could occurdozens, hundreds or even thousands oftimes a day, and the users know howlong it takes when they click “Save.”They also know how long it takes to ac-cess their documents, databases andwebsites. Inject something into theprocess that increases save time or ac-cess time from one or two seconds tothree or four seconds, and watch yourhelp desk light up like a Christmas tree.

This means that the No. 1 rule to keep in mind when introducing achange in your primary data storage system is primum non nocere, or“First, do no harm.” Data reduction techniques can definitely help savemoney in disk systems, and power and cooling costs, but if by introduc-ing these technologies you negatively impact the user experience, thebenefits of data reduction may seem far less attractive.

The next challenge for data reduction in primary data storage is the expectation that space-saving ratios will be comparable to thoseachieved with data deduplication for backups. They won’t. Most backupsoftware creates enormous amounts of duplicate data, with multiplecopies stored in multiple places. Although there are exceptions, that’snot typically the case in primary storage. Many people feel that any reduction beyond 50% (a 2:1 reduction ratio) should be consideredgravy. This is why most vendors of primary data reduction systemsdon’t talk much about ratios; rather, they’re more likely to cite reductionpercentages. (A 75% reduction in storage sounds a whole lot better thana 3:1 reduction ratio.)

If you’re considering implementing data reduction in primary datastorage, the bottom line is this: compared to deploying deduplication in a backup environment, the job is harder and the rewards are fewer.That’s not to suggest you shouldn’t consider primary storage data re-duction technologies, but rather to help you properly set expectationsbefore making the commitment.

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STORAGE

The No. 1 rule whenintroducing a change in your primary datastorage system is primum non nocere,or “First, do no harm.”

Storage April 2010

PRIMARY STORAGE DATA REDUCTION TECHNOLOGIESCOMPRESSION. Compression technologies have been around for decades,but compression is typically used for data that’s not accessed very much.That’s because the act of compressing and uncompressing data can bea very CPU-intensive process that tends to slow down access to thedata (remember: primum non nocere).

There’s one area of the data center, however, where compression is widely used: backup. Every modern tape drive is able to dynamicallycompress data during backups and uncompress data during restores.Not only does compression not slow down backups, it actually speedsthem up. How is that possible? The secret is that the drives use a chipthat can compress and uncompress at line speeds. By compressing the data by approximately 50%, it essentially halves the amount of datathe tape drive has to write. Because the tape head is the bottleneck,compression actually increases the effective speed of the drive.

Compression systems for primary data storage use the same con-cept. Products such as Ocarina Networks’ ECOsystem appliances andStorwize Inc.’s STN-2100 and STN-6000 appliances compress data asit’s being stored and then uncompress it as it’s being read. If they cando this at line speed, it shouldn’t slow down write or read performance.They should also be able to reduce the amount of disk necessary tostore files by between 30% and 75%, depending on the algorithms theyuse and the type of data they’re compressing. The advantage of com-pression is that it’s a very mature and well understood technology. Thedisadvantage is that it only finds patterns within a file and doesn’t findpatterns between files, therefore limiting its ability to reduce the sizeof data.

FILE-LEVEL DEDUPLICATION. A systememploying file-level deduplication examines the file system to see if twofiles are exactly identical. If it finds twoidentical files, one of them is replacedwith a link to the other file. The advan-tage of this technique is that thereshould be no change in access times,as the file doesn’t need to be decompressed or reassembled prior tobeing presented to the requester; it’s simply two different links to thesame data. The disadvantage of this approach is that it will obviouslynot achieve the same reduction rates as compression or sub-file-leveldeduplication.

SUB-FILE-LEVEL DEDUPLICATION. This approach is very similar to the tech-nology used in hash-based data deduplication systems for backup. Itbreaks all files down into segments or chunks, and then runs thosechunks through a cryptographic hashing algorithm to create a numericvalue that’s then compared to the numeric value of every other chunk

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STORAGE

A system employing file-level deduplicationexamines the file systemto see if two files areexactly identical.

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Storage April 2010

that has ever been seen by the deduplication system. If the hashesfrom two different chunks are the same, one of the chunks is discardedand replaced with a pointer to the other identical chunk.

Depending on the type of data, a sub-file-level deduplication systemcan reduce the size of data quite a bit. The most dramatic results usingthis technique are achieved with virtual system images, and especiallyvirtual desktop images. It’s not uncommon to achieve reductions of75% to 90% in such environments. In other environments, the amountof reduction will be based on the degree to which users create dupli-cates of their own data. Some users, for example, save multiple versionsof their files on their home directories. They get to a “good point” andsave the file, and then save it a second time with a new name. Thisway, they know that no matter what they do, they can always revert tothe previous version. But this practice can result in many versions of anindividual file—and users rarely go back and remove older file versions.In addition, many users download the same file as their coworkers andstore it on their home directory. Theseactivities are why sub-file-level dedu-plication works even within a typicaluser home directory.

The advantage of sub-file-level dedu-plication is that it will find duplicatepatterns all over the place, no matterhow the data has been saved. The disadvantage of this approach is thatit works at the macro level as opposedto compression that works at the micro level. It might identify a redun-dant segment of 8 KB of data, for example, but a good compression algorithm might reduce the size of that segment to 4 KB. That’s whysome data reduction systems use compression in conjunction withsome type of deduplication.

A SAMPLER OF PRIMARY STORAGE DATA REDUCTION PRODUCTSThe following vendors currently offer primary storage data reductionproducts (listed in alphabetic order):

• EMC Corp. EMC introduced file-level deduplication and compressionof inactive files in its Celerra filer. Administrators can configure varioussettings, such as how old a file must be before it’s a candidate for thisprocess, and what file sizes the process should look for. While dedupli-cation and compression of older data obviously won’t generate asmuch data reduction as compressing or deduplicating everything, EMC customers have reported significant savings using this data reduction implementation.

• Exar Corp. Exar gained data deduplication technology with its April2009 acquisition of Hifn Inc. End users may be unfamiliar with Exar, but

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STORAGE

The advantage of sub-file-level deduplication isthat it will find duplicatepatterns all over theplace, no matter how the data has been saved.

Storage April 2010

they may already be using their products. Many high-end virtual tape libraries (VTLs) and data deduplication systems for backups use Exarhardware compression cards for data compression. Exar now has released a card, designed to be placed into a Windows or Linux server,that will deduplicate data as it’s being written to any hard drive. Exar’sHifn BitWackr B1605R is a hardware and software product that offloadsdata deduplication and compression from a server’s CPU and makesadding data reduction to a Windows or Linux server a relatively easyprocess.

• GreenBytes Inc. GreenBytes is in something of a unique position, as it’s the first vendor attempting to make a single product to addressthe data reduction needs of both backup and primary data storage in its GB-X Series of network-attached storage (NAS) and storage-area network (SAN) storage devices. The firm uses a hash-based data dedu-plication technology, but the hash algorithm is different from that usedby all other vendors: Instead of the widely used SHA-1, GreenBytes usesTiger, which it says is more suited to general-purpose processors thanSHA-1 and, therefore, offers significant performance advantages whilenot decreasing data integrity. Tiger’s key space (192 bits) is significantlylarger than that of SHA-1 (160 bits), which further reduces the chancesof a hash collision. Green-Bytes is also making exten-sive use of solid-state diskas a cache in front of SATAdisk so that it can bettermeet the performance needsof primary data storageusers.

• Microsoft Corp. With itsWindows Storage Server2008, Microsoft offers file-level single-instancededuplication built into theoperating system. A numberof storage systems vendorsare taking advantage of the built-in SIS, includingHewlett-Packard’s Storage-Works X-series NetworkStorage Systems and Com-pellent’s Storage Center withNAS. File-level deduplicationalone will provide modestspace savings for users of these systems.

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IS ARCHIVING DATA REDUCTION?

Some vendors consider archiving andhierarchical storage management(HSM) to be data reduction technolo-gies. Both archiving and HSM systemscan reduce the amount of disk youneed to store your primary data, butthey do so by moving data from onestorage system to another. While theymay save you money, they’re nottruly reducing the size of the data—they’re just moving it to less-expen-sive storage. Therefore, while theseare good technologies that compa-nies with a lot of data should explore,it’s not data reduction per se.

Storage April 2010

• NetApp Inc. NetApp was the first primary data storage vendor to offer deduplication, which leverages the company’s existing write any-where file layout (WAFL) file system technology. The WAFL file systemalready computes a CRC checksum for each block of data it stores, andhas block-based pointers integrated into the file system. (It’s the se-cret behind NetApp’s ability to have hundreds of snapshots without any performance degradation.) An optional process that runs during timesof low activity examines all checksums; if two checksums match, thefiler does a block-level comparison of those blocks. If the comparisonshows a complete match, one of the blocks is replaced with a WAFLpointer. The result is sub-file-level deduplication without a significantimpact on performance. NetApp’s deduplication system has been testedby many users against multiple data types, including home directories,databases and virtual images, and most users have reported positiveresults in both reduction percentages and performance. As of this writ-ing, NetApp uses only deduplication and doesn’t do compression.

• Nexenta Systems Inc. Nexenta uses the Oracle Solaris ZFS file systemin its NexentaStor family of storage system software products that arebased on the open source OpenSolaris platform; however, the firm hasadded more than 30 additional features to its ZFS-based offering that areonly available from Nexenta. Examples of these features include an inte-grated management console, LDAP integration, continuous data protec-tion (CDP) and synchronous replication.The recently announced NexentaStor3.0 offers deduplicated storage that’sfully integrated with Citrix Systems Inc.XenServer, Microsoft Corp. Hyper-V and VMware Inc. VMware vSphere.

• Ocarina Networks. Ocarina takes avery different approach to data reductionthan many other vendors. Where mostvendors apply compression and dedupli-cation without any knowledge of thedata, Ocarina has hundreds of differentcompression and deduplication algo-rithms that it uses depending on thespecific type of data. For example, thecompany uses completely different techniques to compress images andWord documents. It also understands encapsulation systems such asthe Digital Imaging and Communications in Medicine (DICOM) system.Ocarina will actually disassemble a DICOM container, examine anddeduplicate the various components, and then reassemble the container.As a result, Ocarina can often achieve much greater compression anddeduplication rates than other vendors can realize with the same datatypes.

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While most vendorsapply compression anddeduplication withoutany knowledge of thedata, Ocarina has hundreds of differentcompression and dedu-plication algorithms thatit uses depending on thespecific type of data.

Storage April 2010

Ocarina isn’t a storage vendor; it works with existing data storagesystem vendors that will allow Ocarina to interface with their systems.Ocarina is currently partnering with BlueArc Corp., EMC, Hewlett-Packard, Hitachi Data Systems and Isilon Systems Inc.

• Oracle-Sun. Oracle’s Solaris ZFS file system also has sub-file-leveldata deduplication built into it. As of this writing, there’s not muchavailable information about how well it duplicates data or its perform-ance in user production environments. However, the ZFS website doesstate that there shouldn’t be a significant difference in performancebetween deduplicated and native data, as long as the hash table usedfor deduplication can fit into memory.

• Storwize Inc. Storwize offers an appliance that sits in-band betweenyour NAS (NFS/CIFS) filer and the systems accessing it. It works like the chips in your tape drives that compress data real-time as it’s beingwritten, and uncompresses it real-time as it’s being read. Like the tapedrive chip, it doesn’t hurt performance because it’s compressing thedata at the same speed it’s arriving at the system. In fact, with certainapplications it can even increase performance. One other interestingthing about their system is that files they compress simply appear ascompressed files on the filer. Therefore, if your worst fears happenedand Storwize disappeared one day, all you would need is enough spaceto uncompress the files using standard algorithms.

NEW AND GROWING FASTA little over a year ago, there were virtually no viable options for reducingdata in primary storage. Now there are half a dozen or so, with more onthe way. Given the runaway growth in file storage that most companiesare experiencing, it shouldn’t take long for data reduction technologiesto find their way into many of the products offered by data storage systems vendors. 2

W. Curtis Preston is an executive editor in TechTarget’s Storage Media Groupand an independent backup expert. Curtis has worked extensively with datadeduplication and other data reduction systems.

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Storage April 201022

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A single director-class switch can replace multiple

smaller switches while offering

growth flexibility, high availability

and a bevy of advanced features.

By Dennis Martin

SAN CONSOLIDATION WITH

DIRECTOR-CLASS

switches

tHE HEART OF any Fibre Channel storage-area network (FC SAN) is the switching equip-ment that connects the host servers with the storage systems. This switchingequipment performs basic connectivity between FC devices and can also:

• Determine the type of FC devices that are connected• Handle FC zoning functions• Typically allow connections to other Fibre Channel switches to extend the

storage network There are two basic classes of FC switching equipment: directors and

switches. And while they both perform the same fundamental functions, thereare significant differences between the two switch classes.

Basic FC switches generally have a fixed number of ports and provide basicswitching functions with limited scalability and redundancy within the switch.This type of FC switch is available today from Brocade Communications SystemsInc., Cisco Systems Inc. and QLogic Corp.

Storage April 2010

At the high end of the switch spectrum are the directors, generallyreferred to as director-class switches. Directors are designed and builtwith scalability and high availability in mind. The term “director” has itsheritage in the IBM ESCON Directors of the early 1990s, which weresome of the first versions of storage switching equipment used formainframes. In earlier days, there were several vendors who providedFC directors, but mergers and acquisitions have whittled the FC directormarket to two main providers, Brocade and Cisco (see “Brocade vs. Cisco:A little history,” below).

DIRECTORS DEFINEDThe fundamental architectural difference between FC switches and FCdirectors is that FC directors are designed and built to scale up, and toprovide high bandwidth and high availability. Today’s FC directors arebuilt with a blade-type de-sign, so that additional portscan be added as needed byslotting an additional blade.The current crop of directorscan scale up to several hun-dred Fibre Channel ports in asingle unit by adding bladesthat contain various incre-ments of ports.

The Brocade DCX Back-bone family of directors canbe deployed in single- ordual-chassis configurations,with support for up to 384FC ports in the single chassisor a maximum of 768 FCports in the dual chassis. A smaller version in the Brocade DCX line, the DCX-4S,scales up to 192 ports. Portsfor the Brocade DCX Back-bone directors are added by inserting 16-, 32- or 48-port blades that support 8 Gbps Fibre Channel. The Brocade 48000 Director isthe previous-generation director that’s available in a single-chassis-only

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BROCADE VS. CISCO: A LITTLE HISTORY

Brocade Communications Systems Inc.,founded in 1995, developed its own FibreChannel (FC) switches and was an early leaderin the FC switch market. It’s also integratedtechnologies from the other FC switchingcompanies it has bought or inherited, likeMcData Corp., which Brocade acquired in late2006. McData had its own line of FC switchesand directors and, at one time, had the vastmajority of the FC director-class switch mar-ket. Brocade’s “M-Series” products come fromthe McData product line. Previously, McDatahad acquired switch vendor Computer NetworkTechnology (CNT) Corp. in early 2005; beforethat, CNT had purchased Inrange TechnologiesCorp. in 2003, which had its own high port-count FC directors.

Cisco Systems Inc., a long-time player inEthernet switching, announced its first FCswitch in 2002 and has been growing thatproduct family since then. Currently, Brocadehas the edge in the FC switch and directormarket, but Cisco is a strong competitor.

Storage April 2010

configuration; however, it doesn’t have the local switching capabilitiesof the DCX Backbone.

Cisco MDS 9500 Series Multilayer Directors are available in threemodels, the 9506, 9509 and 9513, and can scale up to 192, 336 and 528ports, respectively. The ports for the Cisco MDS 9500 Series are addedin different increments depending on whether you need 4 Gbps or 8Gbps Fibre Channel. For 4 Gbps FC, the ports are added in 12-, 24- or 48-port increments. For 8 Gbps FC, the ports are added in 24- or 48-portincrements, or a hybrid 4/44 model that has four 8 Gbps ports and 44 4 Gbps ports.

By contrast, regular Fibre Channelswitches typically have a fixed physicalport count, although blocks of portsmay be enabled by a license key to keep the initial acquisition cost low.Port counts for these switches rangefrom eight ports up to 64 or 80 ports forBrocade switches, and 128 ports for theQLogic 9000 in a single switch chassis.

Another advantage that directors pro-vide is that with the large port count in a single unit, it may be possibleto design a SAN fabric with minimal or no inter-switch links (ISLs). ISLs,sometimes known as “hops,” contribute to increased latency and havethe potential to degrade performance if they’re not configured optimally.Often, smaller fixed-port count switches are deployed to get a SAN

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Another advantage thatdirectors provide is thatwith the large port countin a single unit, it may bepossible to design a SANfabric with minimal or nointer-switch links (ISLs).

AT A GLANCE:CISCO AND BROCADE DIRECTOR-CLASS SWITCHES

FEATURE

Maximum number of ports

Fibre Channel (FC) support (both backwardcompatible with 1 Gbps and 2 Gbps FC)

Bandwidth

SAN virtualization

Management

BROCADE DCX BACKBONE

384 FC ports (single chassis),768 FC ports (dual chassis)

4 Gbps FC, 8 Gbps FC and 10 Gbps FC

256 Gbps per slot; local switching up to 384 Gbps

Brocade Virtual Fabrics

Brocade Data Center Fabric Manager (DFCM)and Brocade Fabric OS (FOS)

CISCO MDS 9500 SERIES MULTILAYER DIRECTORS

Model 9506: 192 ports; Model 9509: 336ports; Model 9513: 528 ports

4 Gbps FC, 8 Gbps FC and 10 Gbps FC

192 Gbps per slot (24- and 48-port 8 GbpsFibre Channel Switching Modules); 96 Gbps(4/44 Host-Optimized Fibre ChannelSwitching Module)

Virtual SANs (VSANs)

Cisco Fabric Manager and Device Manager

Storage April 2010

started. As storage growth occurs and the single switch is outgrown, a second switch is added and ISLs are used between the switches toexpand the SAN fabric. As growth continues, a third switch is typicallyadded and so on. At some point in this growth pattern with many smallerswitches and several ports on each switch dedicated to ISLs, many ofthe ports won’t be available to use as device ports (to connect hostservers and storage units), so several hops may be necessary to con-nect a host server at one end of the SAN to a storage device at the other end of the SAN. Directors can alleviate this situation by removingmany or all of the ISLs so that most of the switch ports can be used fordevices rather than dedicating ports to the switching infrastructure.

DIRECTORS DELIVER MORE BANDWIDTHBandwidth is another key advantage of director-class switches for environments that need high total I/O bandwidth. The Brocade DCX directors provide up to 256 Gbps of total bandwidth per slot (or blade)of 16, 32 or 48 ports. The DCX also has a local switching capability thatcan provide up to 384 Gbps of bandwidth for ports in the same portgroup within a 48-port blade. The Cisco 9500 series provides 96 Gbps or192 Gbps per slot (or switching module) of 24 or 48 ports. Each vendorcan provide performance data for theirproduct that shows how well their systems do under heavy loads, but themain point is that they can handle veryheavy loads of storage I/O traffic. In addition, these directors also have thecapability to have several 10 Gbps FibreChannel ports that are used for ISLs to trunk traffic between switches or directors. This ISL capability allowslarge SAN fabrics to be constructed in a core-edge type of topology, whereone or more directors are at the core of the SAN and smaller, fixed port-count switches are deployed at the edge of the SAN. As server virtual-ization becomes more common and the load on physical servers be-comes greater, the need for high bandwidth in the FC infrastructurealso increases and directors become a more appealing alternative to regular switches.

HIGH-AVAILABILITY BENEFITS OF DIRECTORSHigh availability is another design feature of directors. Normally, directorsare deployed in business-critical settings where very high uptime is oneof the key criteria of service-level agreements. Directors typically have

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Each vendor can provideperformance data fortheir product that showshow well their systemsdo under heavy loads,but the main point is thatthey can handle veryheavy loads of storageI/O traffic.

Storage April 2010

redundant components so that there’s no single point of failure. Thiscovers the basics such as redundant hot-pluggable power supplies andcooling fans, and includes redundant core processing and switchingcomponents, as well as redundant World Wide Name (WWN) cards.These high-availability features allow for nondisruptive software orfirmware upgrades.

Some of the redundant componentsoperate in an active/passive mode,where one component is active and the other is in standby mode, ready totake over in the event of a failure of theactive component. If there’s a hardwarefailure on a port or port card in a direc-tor, the port card can be removed andreplaced without losing use of the en-tire director. With an equivalent failurein a fixed port-count switch, the entire switch typically has to be takenoffline for repair or replacement. Directors are designed to stay up andrunning so that host servers don’t lose access to their storage data. Ofcourse, all of the high-availability capabilities add to the cost of thesesystems.

HIGH-END FEATURES OF DIRECTORSDirectors also provide a number of advanced features, some of whicharen’t available in smaller, fixed port-count switches. Directors fromBrocade and Cisco each support the concept of virtual SANs, FICON formainframes, and provide features for long-distance connections usingFCIP, iSCSI, dense wavelength division multiplexing (DWDM), SONET andother protocols. The specific implementations differ slightly when com-paring the two vendors’ products, but these directors are designed to bethe central hub for a complex SAN that not only handles local FC traffic,but can send the Fibre Channel traffic over distances to remote sites.

Because of their modular design, directors can adapt to new require-ments. For example, specialty blades that support connecting to darkfiber, hardware encryption, 10 Gb Ethernet (10 GbE), Fibre Channel overEthernet (FCoE) and other features are available today, and the directors’designs also support future requirements in the same infrastructurewithout having to replace the entire unit.

Management of directors and the SAN fabric is critical, and these directors provide solid management software that can do performancemonitoring, quality of service (QoS) , bottleneck detection, advancedzoning and a myriad of other functions. The directors can also passmanagement data using SNMP to higher-level management softwareplatforms.

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If there’s a hardware failure on a port or portcard in a director, theport card can be removedand replaced without losing use of the entiredirector.

Storage April 2010

ADVANCED CAPABILITIES EQUAL HIGHER COSTFibre Channel switches and directors generally aren’t purchased directlyfrom the manufacturer but through a server vendor, storage vendor,system integrator or VAR. Pricing will vary depending on a number offactors, including your relationship with your supplier. Director pricingcan get expensive, not only for the hardware but for some of the licensekeys. Per-port costs for fully loaded directors are higher than same portcount fully loaded fixed-port switches,in the neighborhood of 2:1 or more, butyou can scale up better with directors;directors also have more high-availabilityfeatures built in.

For some data centers, availablepower is an issue as their electric powerutility companies have indicated that they can’t bring in any additionalpower to handle peak workloads. In these cases, data centers areclamoring for more energy-efficient equipment. Like most IT equip-ment vendors, switch and director vendors are focusing on energy efficiency. Given the ability of directors to consolidate the workloadsof several or more regular switches, the case can be made that amove to directors will yield power conservation benefits, so you canexpect director vendors to emphasize their “green” features.

DO YOU NEED A DIRECTOR?Before replacing your current switching infrastructure with a director,you need to determine your requirements. If you need any of the following,then you should consider a director-class switch:

• High availability in each component of the Fibre Channel infrastructure

• High port count• High total bandwidth• Lower percentage of ports dedicated to ISLsYou’ll have to do some technical analysis to determine your specific

needs, but if any of your requirements point to one or more of theabove, then a director might be good solution.

The trade-offs between using directors and smaller, fixed port-count switches affect your equipment budget and operating budget.Directors are more expensive, but provide more features, as describedpreviously. But you also need to consider the day-to-day managementof your Fibre Channel infrastructure. Are you spending too much timemanaging too many “things”? Would it be easier to manage one largeunit rather than several small units?

You should also consider if your storage infrastructure is in a growthmode, and if you’ll need to add quite a few more ports now and in the

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Director pricing can getexpensive, not only forthe hardware but forsome of the license keys.

Storage April 2010

near future—and all in the same SAN. If so, a director’s ability to addports fairly easily might be a good option. If the additional ports youneed were configured with smaller, fixed port-count switches, youshould also account for the ports that would have to be dedicated toISLs rather than to storage devices and servers.

As noted, if you do opt for one or more directors, you may still beable to use the smaller fixed-port switches that the directors are re-placing. You could use those small switches as edge switches placedclose to the servers or storage systems in a simple core-edge topology.You could also use the small switches to create a standalone testingenvironment.

Generally speaking, there are two good reasons to deploy switchesand directors from the same manufacturer. First, the manufacturers are more likely to guarantee that the equipment is fully compatible with their own equipment. Secondly, you’ve probably already investedtime, experience and money in training and getting comfortable withone brand of switches, so it will be easier to adapt to directors thathave a similar look and feel rather than going through the time and expense of learning new equipment.

Directors can be very effective additions to your SAN, especially asyou build for the future, but you’ll have to carefully examine the featuresand pricing to ensure that they’re the best solution for your shop. 2

Dennis Martin has been working in the IT industry since 1980, and is thefounder and president of Demartek, a computer industry analyst organizationand testing lab.

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Storage April 201030

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THE INFORMATION storage managers want most about their data storage systems probablyhasn’t changed since storage arrays began appearing in the enterprise. These days,however, storage managers need even more than that if they expect to run an efficientstorage operation that addresses business needs as well as storage.

“The basics haven’t changed: how much storage do I have, how much is still avail-able and what is the utilization,” said Bob Laliberte, senior analyst at Milford, Mass.-

SRM TOOLS STRUGGLE TO MEET

today’s demandsAt one time, SRM applications tried to be all things for all storage shops,with little success. Modern data storage environments require new toolsto navigate the intricacies of virtualized environments, but the jury’s stillout on whether storage management vendors can meet those needs.

By Alan Radding

Storage April 2010

based Enterprise Strategy Group (ESG). But Laliberte doesn’t stop there.Storage managers also want to look across multiple storage tiers andarrays from different vendors.

“Of course, we look at the usual metrics to make sure we have enoughstorage capacity,” said a storage manager at a large financial trading firm.However, he wants more than that from his storage resource manage-ment (SRM) tool, Aptare Inc.’s StorageConsole. “We have customers whodo a lot of algorithmic trading, which entails many more orders per trade.That means there’s more data to be stored for each trade,” he explained.The company uses the Aptare application to track the storage activity forchargeback purposes.

Chargeback is just one of the newmetrics storage managers want fromSRM tools. While they’re chasing downthe basic capacity data, they might aswell collect storage-area network (SAN)configuration data, information on net-work paths, and data on backup suc-cess/failure rates with their SRM tool.Others see the need to extend SRM evenfurther, with storage and SAN perform-ance metrics, and visibility into the vir-tualized environment. “We also see SRM providing real-time perform-ance metrics,” said Jeff Boles, senior analyst and director, validationservices at Hopkinton, Mass.-based Taneja Group. In short, storage re-source management has to be about more than just available capacity.

CHANGING SRM LANDSCAPEThe rise of players like Aptare signals a change in the SRM landscape. “The big SRM players of the past are now littered along the side of theroad . . . maybe a few have survived,” said Greg Schulz, founder and senioranalyst at StorageIO Group, Stillwater, Minn. IBM remains with its variousTivoli tools, while Hewlett-Packard (HP) Co. now has Storage Essentials,into which it folded its AppIQ acquisition. EMC Corp. includes SRM in itsIonix family of tools.

Many other management software vendors have been absorbed bybigger players. Onaro Inc., which provided visibility into the SAN, was acquired by NetApp. Tek-Tools Software, a popular small SRM player, wasacquired by SolarWinds, and Quest Software Inc. picked up MonoSphereInc. and its Storage Horizon capacity management tool in 2009. Similarly,IBM acquired NovusCG in 2007, while Opsware acquired CreekPath Systems in 2006 and was then acquired by HP the following year.

Yet fresh players continue to arrive on the scene, Schulz noted. Forexample, SANpulse Technologies Inc., which isn’t exactly a startup, provides analysis and correlation.

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“We have customers whodo a lot of algorithmictrading, which entailsmany more orders pertrade. That meansthere’s more data to bestored for each trade.”

—Storage manager for a financial trading firm

Storage April 2010

“Overall, we’re seeing a shift from the large monolithic, costly SRMtools to lighter, easier to use, more nimble tools,” Schulz said. The oldSRM tools typically required extensive customization and took upwardsof a year to deploy before a company would start seeing real value. “Today’s smaller, lighter tools are relatively cheap and fast to install.The users get value almost immediately,” he added.

Aptare CEO Rick Clark refers to theearlier storage resource managementplayers as SRM 1.0. He dubs new players,like his company, as SRM 2.0.

In addition to their high cost and bigfootprint, the older SRM products also relied heavily on agent technology. Thisnot only slowed deployment, but compli-cated management as each agent be-came a potential problem and expense.The older products also often required afat client on the storage administrator’s desk which, at a minimum,might have to run one or a few Java applets. Agents facilitate the collec-tion of detailed information from the storage arrays of different vendors.

SRM 2.0 tools, by comparison, are generally agentless. If they’re notagentless, “they find creative ways to get around the use of agents bysubstituting a more friendly kind of agent,” StorageIO Group’s Schulzsaid. This often takes the form of an external appliance that knows howto dig out the desired information from each attached storage device.

“Agentless SRM approaches certainly are a lot easier,” said SteveScully, research manager, continuity, disaster recovery (DR) and storageorchestration at Framingham, Mass.-based IDC. “Previously, companieshad to commit to installing lots of agents. In effect, you were adding tothe problem in your attempt to fix the problem.”

Despite the tumult in the storage resource management segmentover the past few years, IDC’s ranking of top SRM vendors hasn’tchanged much. “EMC is the big gorilla in the space with Ionix,” Scullysaid. It’s followed by IBM with its TotalStorage Productivity Center, CA’s Storage Resource Manager and HP’s Storage Essentials products.

The challenge for all of these tools is multivendor information collec-tion. SNIA’s Storage Management Initiative Specification (SMI-S) wassupposed to solve the multivendor challenge, but it hasn’t fully delivered(see “What’s happening with SMI-S,” p. 33). “The problem with SMI-S isthat it’s lowest common denominator,” StorageIO Group’s Schulz said.“Vendors can make extensions, but to really make it work you need touse those or else go directly to the vendor’s API.” The need for extensionsor APIs misses the point of having a management information standard.

Given the disarray in the storage resource management market,many users end up with multiple tools to handle SRM issues. For example,

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The old SRM tools typi-cally required extensivecustomization and tookupwards of a year todeploy before a companywould start seeing realvalue.

Storage April 2010

Gorilla Nation, an Evolve media company headquartered in Los Angeles,uses SRM tools from NetApp to handle SRM on its filers and anotherproprietary SRM tool built into its ParaScale Inc. internal storage cloud.“No [single] SRM tool looks across everything or gives you all the infor-mation you want,” said Alex Godelman, Gorilla’s senior vice president oftechnology. The company handles online advertising sales for severalhundred websites, as well as dozens of its own websites.

Many users simply skip using SRM tools and make do with whatevermanagement tools their storage array vendor provides. LifeScript.com, a woman’s health Web portal based in Mission Viejo, Calif., uses 3PARstorage in its highly virtualized server environment. “We’re very fluid.We might put up a server one day and allocate storage to it and thenscrap it the next,” said Gary Rizo, director of IT operations. For storagemanagement data, the company draws on 3PAR’s reporting tools. “Wewant to know when we’re running out of storage, so we use the 3PARSystem Reporter to configure alerts when we approach a threshold,”Rizo explained.

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STORAGE

WHAT’S HAPPENING WITH SMI-S

SNIA’s Storage Management Initiative Specification (SMI-S) is alive and well.Once touted as bringing storage management nirvana by which storagemanagers could collect, consolidate and analyze data from every storagedevice in their environment regardless of vendor, SNIA today has more real-istic expectations for the standard. Rather than replace device-specifictools, SMI-S enables a base level of information that storage vendors canextend as desired.

Officially, SMI-S defines a method for the interoperable management ofa heterogeneous storage network and presents the information to a Web-based enterprise management (WBEM) client from an SMI-S-compliantcommon information model (CIM) server and an object-oriented, XML-basedmessaging interface designed to support the specific requirements ofmanaging devices in and through SANs. In plain English, it defines a way for standards-compatible tools to get at sets of common information fromSMI-S-compliant storage devices.

Interoperability testing has already begun on SMI-S Version 1.4. However,SMI-S only takes you so far; data storage administrators will still needdevice-specific tools and vendor APIs and CLIs to perform certain tasks. Formost routine tasks—approximately 80% of what an administrator does dayto day—SMI-S alone should be sufficient, according to Wayne Adams, seniortechnologist and director of standards within the Office of the CTO at EMCCorp., as well as SNIA’s chairman.

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Storage April 2010

NEW SRM METRICSStorage administrators still need the basic metrics around availablestorage. “They want to get a handle on capacity; what’s available andwhen they’re going to run out,” IDC’s Scully said. In the decade or moresince SRM appeared, however, the IT infrastructure has changed, growing far more complex. This complicates the storage resourcemanagement challenge.

Virtualization, for example, creates problems for storage admins. “Youlose visibility,” Scully noted. “You no longer see a one-to-one server-storage relationship.” Now storage admins need automated discoveryand path mapping from the application and the virtual machine to thephysical server, through the network switch to the storage array anddown to the LUN and file system. Throw all of that into a multivendor environment and the complications snowball.

Today’s heightened focus on governance, risk and compliance (GRC)also puts new demands on storage resource management. “You needthe SRM tool to track storage usage against policies,” Scully said.

Still, Scully hasn’t sensed any clamor at the storage admin level fornew SRM metrics. “Many are too busy just trying to keep up to thinkabout new metrics. This is really a higher-level IT concern,” he said, that shows up at the data center level.

The new SRM metrics fall into three broad categories: performancemetrics, backup and disaster recovery metrics, and green metrics (see “New SRM metrics,” at right). The “green” category is only just emerging.

PERFORMANCE METRICS“In terms of performance, I want to see metrics thatshow choke points by meas-uring throughput on the array, the cache, by RAIDgroup or the switch,” saidthe trading firm’s manager.Aptare gives him everythinghe needs in terms of capaci-ty management and charge-back. To get visibility intopotential choke points alongthe end-to-end storageprocess, he turns to toolsprovided by his array andswitch vendors.

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STORAGE

NEW SRM METRICS

These new storage metrics, based on inputfrom storage administrators and analysts,should find their way into future storage management products and practices:

• Cost per IOPS

• Kilowatt per IOPS

• Kilowatt per unit of bandwidth

• Kilowatt per TB

• Backup errors per night/week

• Speed to recover disk/file/server

• Storage usage per user/application/business unit

• Storage usage by tier/HBA/LUN

• Storage compliance with SLA

Storage April 2010

For the Law School Admission Council Inc. in Newtown, Pa., a serviceprovider to its member law schools, performance management requireskeeping close tabs on available capacity, especially during its busy sea-son. Using HP’s Storage Essentials, the school monitors changes in capacity. “We try to be proactive,” said Jerry Goldman, director of technical services. “We can add capacity on the fly or clear out data.”He said that when a capacity threshold hits 85% it gets checked everysix hours; when it reaches 90%, the warnings come every three hours.If it hits 95%, the storage people are onit hourly.

Tom Becchetti, the Unix and storagemanager at a midsized medical researchinstitution, has lately started payingmore attention to performance. “Nowthat everything is virtualized, it’s drivinghigher I/O. So I’m concerned about re-sponse time in IOPS,” he said. Their usualSRM tools don’t show end-to-end performance, so he’s looking for toolsthat operate at the subsystem level.

“A lot of SRM tools are missing performance metrics, especiallyaround IOPS,” StorageIO Group’s Schulz added.

BACKUP AND DISASTER RECOVERY METRICSFor some IT managers, backup and disaster recovery metrics have becomeimportant. “I’d like to see metrics on how quickly we can recover a web-site. If I have a certain amount of storage, how long will it take me torecover in the event of a failure?” LifeScript.com’s Rizo queried.

The financial trading firm is also concerned with backup and recoverymetrics. “We’re an ITIL [Information Technology Infrastructure Library]shop and have to meet specific backup and recovery service targets,”said their storage manager. Aptare gives him reports on successfulbackups, which he can massage for trending.

While companies are looking at backup and disaster recovery metrics,they should also look at replication performance and success/failure.“The same SRM tool should report on replication errors and what kind of errors they were,” StorageIO Group’s Schulz said.

GREEN METRICSGreen storage resource management metrics have barely begun to takehold. “No customers are asking us for green storage metrics. There arenot yet tools to expose that data,” said Kalyan Ramanathan, HP’s directorof business service management. Aptare’s Clark added: “Most storagecomponents don’t give power consumption. Even their APIs and CLIsdon’t give that information.” Once storage vendors can expose thatdata, SRM tools will be able to grab it.

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STORAGE

“A lot of SRM tools aremissing performancemetrics, especiallyaround IOPS.”

—GREG SCHULZ, founder and senior analyst, StorageIO Group

Storage April 2010

But some storage managers see potential benefits from gatheringgreen metrics. “Take something like kilowatts/TB. Changes in a numberlike that could be an early predictor of a disk problem,” said John Wonder,an independent storage consultant in San Mateo, Calif. Other storage-related energy metrics, such as energy cost per TB, he suggested, mightbe valuable in a large data center or in a location where energy availabilityis severely constrained.

WHAT’S IN A NAME?Given the emerging interest in new storage metrics and the growing useof virtualization, the storage resource management label is perhaps outof date. With interest in wide and deep end-to-end visibility, StorageIOGroup’s Schulz suggested that “SSRM”—systems and storage resourcemanagement—would be a more appropriate term in this virtualized IT era.Trying to monitor and measure storage performance without looking atswitch ports and servers, both virtualized and physical, will be increasinglyfrustrating. 2

Alan Radding is a frequent contributor to TechTarget sites.

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STORAGE

Storage April 201038

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rhot spots | lauren whitehouse

The modernization of backup: More disk, less tape

ESG’s 2010 Data Protection Survey shows that the trend away from tape continues,

with the economics of both deduplication, for disk-based backup, and cloud storage, for

long-term retention, contributing to tape’s decline.

ANKED AS THE No. 3 IT priority by more than 500 respondents to ESG’s 2010 IT Spending Intentions Survey, “improving data backup and recovery” takespriority over a number of other IT initiatives and was edged out only by “increasing the use of server virtualization” and “information security initiatives.” And among backup and recovery projects, disk-assisted dataprotection is expected to dominate this year and beyond. The introductionof disk to improve the speed and reliability of backup and recovery is a topconsideration for companies of all sizes—especially as data deduplication changes the economics of the investment. And whiletape-based strategies are often requiredand even desired for long-term retention,the economics of introducing a cloud stor-age tier for this purpose looks promising.

And in its recent 2010 Data ProtectionSurvey of more than 500 IT professionals,ESG found that transitioning from tape- to disk-based backup is one of the majorforces in modernizing backup and recovery. According to the results, respondents have made strides to minimize the use of tape in backup andrecovery processes since the 2008 survey. Today, 20% of those surveyed“back up directly to tape only” vs. 33% in 2008, 62% cite “back up to diskand tape” compared to the 53% noted in 2008, and 18% now “back up todisk only” vs. 14% two years ago.

Companies that are smaller in size (based on the number of employees,number of production servers, capacity of data and data protection spending)are more likely than larger companies to maintain their “tape hugger” statusand deploy tape-only strategies. For example, 30% of organizations withfewer than 25 production servers employ tape-only backup, whereas only15% of organizations with more than 500 servers rely solely on tape backup.However, organizations with fewer than 25 production servers (26%) arealmost twice as likely to deploy disk-only backup strategies vs. those with

Among backup andrecovery projects,disk-assisted dataprotection is expectedto dominate thisyear and beyond.

Storage April 2010

more than 500 servers (16%). Why do small companies have such diver-gent postures when it comes to tape vs. disk? Most likely, it’s becausethe decision of tape vs. disk isn’t just about the size of the company.It’s more about the types of systems inplace and the criticality of data to run thebusiness. For example, a small (in terms of number of employees) law firm mightbase 90% of its productivity and intellec-tual property in IT-based systems, where-as another small company might be muchless reliant on IT systems; because of this,the two companies are likely to approachtechnology decisions—such as the issueof tape vs. disk—very differently.

Slicing the data a little differently, ESG found organizations thathave made the full transition to disk-based backup are evenly splitamong midmarket (those with 100 to 999 employees) and enterprise-sized (1,000 or more employees) companies.

The majority of survey respondents rely on some combination ofdisk and tape—possibly using disk-based protection for certain tiers of application data and tape for others, or using disk as a staging areafor backup before moving copies to a tape tier of storage. Survey re-spondents with 500 servers or more were more likely than those withfewer than 25 production servers to adopt this strategy (68% vs. 44%,respectively). This is probably because larger companies have beenperforming tape-based backup for dozens of years and have the infra-structure and people to manage it. They may also be forced (for com-pliance or other reasons) to maintain data for a longer term than asmaller company, and so many of those larger companies believe thattape is the best long-term retention media. Smaller organizations thatsee tape as antiquated and cumbersome may be more apt to changeit up and stay current, especially if their VAR convinces them that itcan provide a better level of service from a remote location.

For those maintaining backup data on disk and tape, the retentionperiod on disk varies (again) by company size. Midmarket companiesare more likely to retain data on disk for less than one month (39% vs.28% at enterprise companies), while enterprise companies are morelikely to retain data on disk for more than six months (31% vs. 21% atmidmarket companies).

Data deduplication may be a factor in this decision because it iden-tifies and eliminates redundant data, thereby reducing the capacity ofdata stored on disk. Enterprise organizations are more likely (45%) thanmidmarket organizations (29%) to use deduplication. This gap widenswhen comparing sites with fewer than 25 production servers (20%) to

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STORAGE

The decision of tapevs. disk . . . is moreabout the types ofsystems in place andthe criticality of datato run the business.

Storage April 2010

those with more than 500 servers (62%), with the larger sites threetimes more likely to employ deduplication.

The shift to disk from tape is likely to continue. ESG survey respon-dents were asked to estimate the percentage of their organization’stotal volume of backup data expected to be stored on different storagemedia types. By 2012, backup data stored on internal server storage isexpected to decline by 9%, backup data stored on external disk-basedstorage systems is expected to increase 14%, and backup data on on-premises tape storage is expected to decrease by 31%.

When it comes to getting backup copies of data offsite for disasterrecovery purposes, methods vary. Backup copies are most often movedoffsite via removable media, such as tape. However, with disk storage inplay, some organizations are opting to electronically vault backup dataover a wide-area network (WAN) connectionto a second site or third-party provider,with larger companies three to four timesmore likely than smaller ones to elect a third-party storage service provider.Eighteen percent of companies don’tmaintain offsite copies at all, with com-panies with fewer than 25 productionservers three times more likely thanthose with 500 or more productionservers to engage in this risky behavior.

The outlook for these offsite techniques in two years? The trendaway from on-site tape extends offsite. Leveraging off-premises disk is expected to increase by 18%, while off-premises tape is expected todecrease by 18%. Taking advantage of a third-party service provider’sstorage is likely to increase by a whopping 40%. The economics ofelectronically vaulting backup copies to cloud-based storage tiers maybe, depending on an organization’s individual circumstances, more at-tractive than maintaining an on-premises tape infrastructure, absorb-ing the overhead of tape operational staff, paying the service fees foroffsite transportation and storage of tape media, and living with thesecurity risk introduced when backup media is transported offsite. 2

Lauren Whitehouse is an analyst focusing on backup and recovery softwareand replication solutions at Enterprise Strategy Group, Milford, Mass.

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STORAGE

Leveraging off-prem-ises disk is expectedto increase by 18%,while off-premisestape is expected todecrease by 18%.

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Tape may be teetering, but it’s still a big part of backup opsYOU HAVE TO SEARCH far and wide these days to find a company that’s not using disk to somedegree in their backup operation. In our latest Snapshot survey, only 6% of respondentssaid they don’t use disk at all for backup. On the flip side, 18% have completely eliminat-ed tape from their backups. Among those companies that do use disk, the methods breakdown relatively evenly, with many companies using more than one disk-based tech-nology. The most popular way to use disk was simply as a file system that acts as the backup target (53%). Just using disk as a staging area or temporary cache before spin-ning off to tape was a close second at 49%, while 37% said they use virtual tape libraries(VTLs) for backup. But tape’s days are far from numbered despite an apparent overall decline. In fact, 39% of those surveyed said they’ll buy tape gear this year, with 55% planning to purchase new libraries. And perhaps more telling evidence about tape’s stay-ing power is the 79% of disk-backup users who say that all or some of their backup data eventually finds its way onto tape. —Rich Castagna

“We would like to implement a disk/VTL solution with dedupe; however, we cannot cost justify it over what we pay for maintenance and tapes.”

—Survey respondent

snapshot

32%Our use of

tape has notchanged

significantly inthree years

27%We still use

tape, but lessthan we did

three years ago

18%We don’t use

any tape in ourbackup process

23%We use tape

more now thanthree years ago

Compared to three years ago, how would youcharacterize your company’s use of tape

in your backup operations?Less than 30 days

30 days to 60 days

60 days to 90 days

Longer than 90 days

How long does your backup data stay on disk before being spun off to tape?

67%

15%

9%

23%We use tape more now than we did

three years ago

Why doesn’t your company use disk in its backup process?

42% We are currently evaluating using disk as a backup target

29% We need to use removable media for backup to ship backup data offsite

16% Backing up to tape is adequate for our needs

16% We have made substantial investments in tape technology

16% We will begin to use disk as a backup target this year

10% Adding disk as a backup target would complicate our processes

Multiple selections permitted

0% 10 20 30 40 50 60 70

9%

Storage April 2010

Storage April 201042

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STORAGE

AdvizeX Technologies, page 7Product Solutions: Storage

EMCBackup and Recovery: Accelerating Efficiency and Driving Down IT Costs Using Data Deduplication

The ROI of Backup Redesign Using Deduplication: An EMC Data Domain User Research Study

Hewlett-Packard CompanyProtecting Data in a VMware Virtualized Server Environment

Backup and Recovery of Microsoft® Hyper-V™ Server Environments

Hitachi Data Systems, page 10Pile on the Savings: Free Storage Virtualization Software from Hitachi Data Systems

White Paper: The Economic Effects of Storage Virtualization

NetApp, page 12Managing Data Growth, Improving Performance, and Enhancing Disaster Preparedness with Storage and ServerVirtualization

Best Practices Business Case Study: Assessing Storage Efficiency Within NetApp's Data Center

Ocarina Networks, page 4Ocarina ECOsystem Technical White Paper

Ocarina Case Study: Cornell Center for Advanced Computing

Permabit, page 17White Paper: Dedupe 2.0 -- The Next Step in Data Deduplication

Calculate How Much Dedupe 2.0 Can Save Your Company

RADirect, page 26Nexsan RAID Storage: SATA and SAS Arrays

Nexsan SATABeast: Up to 84TB in 4U as Low as $875/TB

Check out the following resources from our sponsors:

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