04 Choosing to Wait on Virtualization Cost may be a factor, but the arguments against virtualization are getting weaker. BY STEPHEN J. BIGELOW

12 How Can the Open Virtualization Format Help You?Use VMware’s command-line utility to import and export OVF packages to and from a wide variety of products. BY DAVID DAVIS

17 Critical Decisions for Virtualization StoragePerformance and existing investments should be considered when planning storage for virtualized environments. BY RICK VANOVER

virtu lDATA CENTER

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Volume 20

RE YOU ON the virtualiza-tion bandwagon yet?Some organizationsstill aren’t on board,and they have somepretty good reasons.

Cost is the biggest barrier to entry.The added expense of updating hard-ware, software, storage and networkarchitecture is enough to stall virtualiza-tion projects until bottom lines start tomove upward. Management complexity is keeping

some organizations away. For smallershops that have endured rounds of lay-offs, the burden of adopting virtualiza-tion may simply be too much to handleright now. Still others think they’ll havea hard time justifying the need for virtu-alization to upper management whenany budget increase is highly scrutinized.Virtualization can be a difficult propo-

sition for many organizations, but high-lighting the return on investment maybe its best selling point. Read Stephen J.Bigelow’s “Choosing to Wait on Virtual-ization” for ideas on how to move virtu-alization up on the priority list.The biggest impact that virtualization

has had on today’s data centers is proba-bly the growing reliance on shared stor-age. Virtualized installations can providebetter management by moving all stor-

age requirements from underusedresources to a centralized system such asa storage area network (SAN). But per-formance and management challengescan pile up quickly for a SAN thatabsorbs a virtualization implementation.Storage touches every part of a virtual-

ized infrastructure, so do it right. RickVanover covers the criteria you need toconsider when planning storage in virtu-alized environments in “Critical Deci-sions for Virtualization Storage.”You might know that the Open Virtu-

alization Format (OVF) specification isan open standard created by VMwareand a number of other companies topackage and distribute virtual machines.What you may not know is that there isan OVF tool that supports the importingand exporting of OVF packages. Because the OVF tool uses a command-

line interface tool, it can involve a bit ofa learning curve. But success is withinreach with step-by-step instructionsfrom David Davis on how to import aVM with the OVF tool in “How Can theOpen Virtualization Format Help You?” Do you have any virtualization tips to

share? Send them our way at ccasatelli@techtarget.com. �

CHRISTINE CASATELLI

Editor, Virtual Data Center

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Weighing Virtualization

A

IRTUALIZATION is arguablyone of the most impor-tant data center technolo-gies to emerge in the lastdecade. By abstracting the

application from the physical hardwarethat runs it, virtualized workloads are farmore flexible, mobile and available thantraditional applications running on non-virtualized hardware. In fact, virtualiza-tion technology has permeated IT soquickly and thoroughly that it’s hard toimagine a business without it. Still, deploying and managing virtual-

ization presents a variety of challengesthat some organizations just can’t handleby themselves. For data centers thataren’t on board yet, it’s time to examinethe principal concerns that are stallingthe adoption and expansion of virtualiza-tion and look for ways to address thoseissues.Perhaps the biggest sticking point for

virtualization is cost. In a recentTechTarget survey that questioned morethan 900 IT professionals about datacenter virtualization from July to Sep-tember 2009, 28% of respondents said

they avoided virtualization because it’sjust too expensive (see Figure 1, page 4).

COST AS A DEAL-BREAKERThat’s no big surprise. Virtualizationoften requires newer and more powerfulserver hardware that can adequatelysupport the performance of numerousvirtual workloads. Doing that mayrequire a server with four, eight or even16 CPU cores, along with up to 16 GB ofmemory or more. Nearly 20% of respon-dents indicated that their existingservers were not adequate but that buy-ing new servers wasn’t an option.Network architectures may also need

to be updated before adopting virtualiza-tion. For example, a single 1 Gbps net-work connection may be totally inade-quate to support the traffic from 10 or20 virtual machine (VM) instances atthe same time. Storage is another areathat is frequently overlooked. Virtualiza-tion deployments are best served withfast Fibre Channel SAN for VM imagesand periodic snapshots.The costs of virtualization are further

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exacerbated when high-availability (HA)and disaster recovery (DR) strategies areadded to the mix. Both strategies requirethe deployment of additional servers andstorage that can boost costs. For exam-ple, even though consolidation canreduce the total number of physicalservers, implementing an HA workloadwill require a second server to hostduplicate VM instances. It’s a similar consideration for off-site

DR facilities. Storage requirements

increase and so do server counts—if it’sa warm or hot site. The bandwidth that’sneeded to move huge volumes of dataacross significant distances can have amajor impact on WAN costs.The cost of virtualization software can

vary, but it must be included in any costevaluation. For example, Hyper-V is partof Microsoft Windows Server 2008 R2,but you pay for each license of WindowsServer. You can get Citrix Xen-Server forfree, but Citrix Essentials for XenServer,

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Figure 1

DODGING THE BULLETSurvey respondents cite a handful of reasons why virtualization

winds up on the back burner.

SOURCE: TECHTARGET

0 5 10 15 20 25 30

Too expensive

Too complex

Not enough servers/apps

Inadequate servers

Server utilization not a problem

No budget until 2010

Non-IT executives won’t approve expenses

Waiting for prices to fall

Apps not a good fit

Waiting for Microsoft options to mature

Lack of in-house management

Lack of in-house installation

Waiting for XenServer options to mature

which includes support and manage-ment tools, still carries a hefty price tag. “The [Citrix XenServer] Platinum is

going to cost you $2,000 to $5,000 perserver,” said Ty Hacker, director of tech-nical sales at I-Business Network, anapplication service provider in Marietta,Ga. “And that feature set basicallyincludes storage management and high-availability.” It’s a similar story with VMware—

starting with VMware Server for freeand then moving to paid versions withenterprise features and tools.Then there’s the cost of labor to install

and set up new hardware, retire or real-locate old hardware, install and config-ure the virtualization platform and pro-vide ongoing management for thatplatform into the future. This includesthe costs for the virtualization platform. “It’s not just the licensing itself. It’s

the support and maintenance over timeas well,” said Mark Bowker, senior ana-lyst at Enterprise Strategy Group, an ITanalyst and business strategy firm inMilford, Mass. “It’s not something thatgoes away. You have that for life.” For smaller shops and IT groups that

have had layoffs and budgets slashedover the last few years, the burden ofadopting virtualization may simply betoo much to handle right now.And finally, there are budgetary issues

that underscore the sensitivity to cost.Sixteen percent of survey respondentssaid that budget approval for virtualiza-tion won’t come until sometime in 2010.Another 12% said that non-IT executiveswon’t approve expenditures for virtual-ization, while an additional 12% ofrespondents are waiting for the price ofall virtualization options to be reduced.

Part of the problem is poor communi-cation. The move to virtualization is ulti-mately a business decision, so IT mustbe able to express the goals of a virtual-ization initiative in a way that makesimmediate sense to management. Forexample, making the case for virtualiza-tion from the standpoint of enhancingavailability or enabling superior DR andrecoverability may be just the argumentneeded to interest upper management.Timing is another issue that can delay

virtualization approval. Hacker said thatthe strongest case for virtualization isoften made when infrastructure hard-ware is reaching its end of life or lease.The prospect of acquiring fewer next-generation servers through consolida-tion can be a compelling motivator formanagement. If there’s still life left inthe equipment, virtualization’s need fornewer and more powerful equipmentmight just get the initiative shelved.

DEPLOYMENT AND MANAGEMENT COMPLEXITYTechTarget survey respondents whoopted to wait on virtualization also dis-closed a range of complexity worrieswhen it came to deployment and man-agement of the technology. More than22% of respondents said that virtualiza-tion was just too complex. Another 11%said they were waiting for Microsoftoptions to mature, while 7% were wait-ing for XenServer options to mature. Respondents who said they were con-

cerned about product maturity shouldtake a fresh look at the three major virtu-alization platforms, which show signsthat they are ready for enterprise-classdeployment.

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Perhaps the biggest area of develop-ment for virtualization platforms isensuring security between VMs. “Right now the technology is probably

ahead of where most people are withtheir deployments,” Bowker said, addingthat organizations that are virtualizing30% to 40% of their infrastructureswould probably benefit from better inte-gration. But he said organizations thatare still virtualizing 20% to 30% of theirinfrastructures should find virtualizationplatforms well suited for deploymenttoday.Survey respondents also said they are

holding off on virtualization because of alack of skills. Almost 10% of respondentscited a lack of in-house managementskills, while almost 9% worried about alack of in-house installation skills.Although there is no specific skill set orcertification level that would lend itselfto a successful virtualization rollout,experts point out that virtualizationadministration is often a cross-platformor cross-discipline endeavor. Data center managers don’t need to be

recognized experts in any one area, butthey should understand the implicationsand relationships among their servers,applications, storage and networking.They may also find value in fresh evalua-tions of current platforms. “XenServerhas been simplified to the point where—even if you didn’t have that skill set orthat exposure back in the early adoptiondays—you would easily be able to get adeployment done,” Hacker said.Comprehensive proof-of-principle

testing is one way to manage the percep-tion that virtualization is complex. Test-ing is a valuable way to overcome initialadoption jitters in areas such as setup,

provisioning or management. Testing isalso crucial when planning to expandthe deployment of virtualization to more mission-critical workloads such as Microsoft Exchange. Some organizations with limited IT

resources may choose to address thecomplexity of virtualization by hiring anoutside contractor or VAR that can per-

form the evaluations and proof-of-prin-ciple testing. The VAR can also handlethe initial rollout and management andthen provide training and support soorganizations can eventually assume fullcontrol over their projects.In addition, survey respondents

expressed concern about their applica-tions and almost 11% said they decidedto wait because they felt the applicationswere not a good fit for virtualization.Homegrown or custom-developed appli-cations may still prove problematicwhen virtualized, but experts have saidthat the concern has largely fallen by thewayside for commercial Windows appli-cations. “I have not seen anything that works

in Windows Server 2003 that doesn’twork in a Windows Server 2003 virtual-

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Perhaps the biggestarea of development for virtualization platforms is ensuringsecurity between VMs.

ized environment,” said Scott Roberts,director of information technology forthe town of South Windsor, Conn. “Wehave not experienced any major failureof an application because it was virtual-ized.”Although the success rate for virtual-

ized commercial applications is gener-ally quite high, vendor support for virtu-alized applications is still spotty. Bowkersaid that virtualization plans shouldinclude the application vendor and aserious discussion about the vendor’ssupport policy if the application is virtu-alized. A critical vendor reneging onsupport can have a huge impact on thesuccess of a virtualization initiative.

JUSTIFYING THE NEEDSurvey respondents also expressed significant worries about justifying themove to virtualization. Nearly 20% ofrespondents said that the move did notmake sense for the number of servers or applications that were in service.Another 19% said that server utiliza-tion was not a big enough problem to prompt the use of virtualization. At first glance, it might seem like

SMBs would have the most trouble justi-fying virtualization—to a point.It’s true that it’s hard to justify virtual-

ization when there is little hardware toconsolidate, no SLAs to guarantee, nocritical uptime requirements or no con-

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Figure 2

MAKING THE ARGUMENTBefore adopting virtualization, it’s important to have a solid justification andclear vision of the role that the technology will play in the organization.

SOURCE: TECHTARGET

0 10 20 30 40 50 60 70 80

Server consolidation

Reduced hardware costs

Power savings/better resourceutilization

Disaster recovery or backup

Test and development

Dynamic load balancing andscheduling

Desktop virtualization

Need to run legacy application

Need to run Windows/other OS

crete recovery goals. But times arechanging, and the needs of SMBs aremore urgent than ever. For example, an SMB with five ser-

vers may depend on 24/7 e-commerceresources to generate revenue. As aresult, the justification for SMBs is notjust a matter of hardware consolidation,although the prospect of running threeworkloads on one server can still be a bigwin for a small business. But today, it’soften more about embracing the businessvalue of availability, backup and recoverythat virtualization makes possible.A major speed bump for virtualization

is not the initial cost. Rather, it’s failingto recognize the return on that invest-ment. Bowker said that most companiesare not able to achieve the promises ofvirtualization right away, and this canskew the perception of the return. With virtualization, it’s about the

expectation of the technology versus thereality of the deployment. “We still seelow consolidation ratios out there—three-, four- and five-to-one virtualmachines per physical server,” he said.“But from a technology perspective, yousee the virtualization vendors promising10, 20, 40 virtual machines per physicalserver.”Research and testing are vital for any

project justification. Take the time toevaluate the available platforms andhave a frank discussion about the results.The decision to virtualize—and yourselection of platforms—will have a long-lasting impact on your organization.“Once you get involved in it, you also

realize that it’s not easy to just changemidstream when you invest all that time,effort, labor and money,” Roberts said,adding that the time and labor are often

more expensive investments than theoutright cost of the platform.Finally, don’t overlook the value of

VARs. The services of a VAR can oftenovercome a lack of time or in-houseskills. An IT department grappling with

day-to-day operations can engage a VARto perform the initial planning, deploy-ment and setup of a virtualized environ-ment and then provide training thatallows the staff to take over manage-ment. The organization may approachthe deployment in phases, using theVAR for each subsequent planning anddeployment phase, and then transfercontrol to the in-house staff.Let the VAR make a strong case for

ROI. The trick is to do your homeworkand find a VAR that is well versed in vir-tualization technology, familiar with theneeds of your vertical market and expe-rienced enough to handle projects thatmatch your scope. �

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Take the time to evaluate the availableplatforms and have a frank discussionabout the results. Thedecision to virtualize—and your selection ofplatforms—will have a long-lasting impact on your organization.

IRTUALIZATION makesservers and applicationscompletely portable,which makes distributingvirtual machines (VMs)

and their pre-installed applications sim-ple. Taking advantage of this, VMwarecreated the virtual appliance market-place where thousands of VMs withapplications—called virtual appli-ances—are available for download, mostat no cost. Some issues existed, though. One was

making these virtual appliances compat-ible with all of VMware’s virtualizationplatforms. Another was allowing datacenter managers to distribute the appli-ances in a single file. Still another wasallowing creators of appliances to cus-tomize the VMs for users at the time ofdeployment. These issues eventually ledto the creation of the Open Virtualiza-tion Format (OVF). For those who aren’t familiar with it,

the OVF specification is an open stan-dard created by VMware and a numberof other companies. The specificationwas proposed to the Distributed Man-

agement Task Force (DMTF), which is anot-for-profit association of industrymembers dedicated to promoting enter-prise and systems management andinteroperability. The OVF standard wasmade available as DMTF specificationversion 1.0.0. According to VMware, OVF is said to

offer some benefits, including:

� An improved experience for anyonedownloading a virtual appliance.

� Virtualization platform independ-ence and flexibility.

� Easy distribution of complex andpreconfigured multi-tiered applica-tions.

� Easy delivery of enterprise software. � Platform-specific enhancements andeasy adoption of advances in virtual-ization through extensibility.

Essentially, by packaging appliances inOVF and by downloading OVF files, datacenter managers can gain efficiencies indistribution and portability. Downloadable from its site, VMware

has an OVF tool, which is a conversion

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How Can the Open Virtualization Format Help You?USE VMWARE’S COMMAND-LINE UTILITY TO IMPORT AND EXPORT OVF PACKAGES TO AND FROM A WIDE VARIETY OF PRODUCTS. BY DAVID DAVIS

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program that supports the importingand exporting of OVF packages. You cancreate OVF packages to distribute to oth-ers and deploy OVF packages into yourvSphere infrastructure without the OVF

tool. However, the OVF tool is what willallow you to do these things at the com-mand line.Not only does the tool put OVF pack-

ages—virtual appliances—into your invSphere infrastructure and export VMsto OVF packages, but it also has a lot ofconversion uses. For example, you canconvert an OVF file to a .VMX file, an.OVA to a .VMX and others. The OVFtool works with vSphere vCenter andwith standalone ESX servers, Worksta-tion 5.x and later, VMware Server 2.xand VMware Studio 1.0 and later. You can download the OVF tool for

both 32-bit Windows and 32-bit or 64-bitLinux. But, the single best place toaccess the download links and OVF tooldocumentation plus participate in agreat forum dedicated to the OVF tool isthe VMware’s OVF community. The OVF tool for Windows download

is a 12MB file and installs quickly. Makesure that you take note of the directorythat it is installed in because that is the

directory that you will have to CD to inorder to use the OVF tool. Unlike other tools that you install, you

won’t find an icon or program group inthe Windows Start Menu for the OVFtool. To use it, you will have to open aWindows or Linux command prompt,put the CD into the installation folder,and run the OVF tool. Ready to learn how to use the OVF

tool? Because it uses a command-lineinterface tool, there may be a bit of alearning curve. Once you finish the com-mand string you use with the OVF tool,save it to a notepad file so that it wouldbe quick and easy to use the OVF toolagain. Fortunately, the OVF tool comes with

more than the average amount of help.Not only can you run OVF tool help, butyou can also run OVF tool help exam-ples, OVF tool help locators and OVFtool help config. VMware has alsoposted a handy online OVF tool userguide.

IMPORTING A VM WITH THE OVF TOOLYou can use the OVF tool with a numberof platforms, and you can perform vari-ous conversions. Still, most will likelyuse the OVF tool to import—or deploy—and export VMs or appliances intoand out of vSphere where you havevCenter in use. Below are some of theoptional switches that you can enable toperform tasks such as creating a customname for the VM in the vCenter inven-tory or powering on the VM afterimport: The basic syntax of the OVF tool is: OVFTOOL (source) (target)

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You can download the OVF tool for both32-bit Windows and 32-bit or 64-bit Linux.

Thus, if you were importing an OVFfile—a virtual appliance—into vCenter,it would be: OVFTOOL (path to OVF FILE)

(vCenter server and inventory

path info)

If you were exporting a VM, the sourceand target would be reversed. In this case,I have opted to download the VMwarevSphere Management Assistant (vMA).This is a free VMware virtual appliance,distributed in OVF. Just like the OVFtool, all you need to download it is a freeVMware username and password. Al-though it’s possible to run the OVF tooland specify the URL to download vMAor another OVF file, I opted to downloadthe vMA OVF and import it myself. In this example, “vCenter server and

inventory path info” is actually a locator.

A locator is a string that tells the OVFtool exactly where in the vSphere infra-structure you want this appliance to beimported. It is likely one of the morecomplex aspects of using the OVF tool,so make sure you read the special helpfile. Here is what a locator might look like: vi://vCenter40/Bandon,

OR/host/Prod/esx3.wiredbrain-

coffee.com

This is telling the OVF tool exactlywhere in the vSphere infrastructure toplace the virtual appliance. This exampleused the following OVF tool commandto import the vMA appliance: ovftool --datastore=ESX3-

datastore1 name="vMA4" --

powerOn "C:\Users\david\Desk-

top\vMA-ovf-4.0.0-161993\vMA-o

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Figure 1

Importing the vMA OVF file to a vSphere server.

vf-4.0.0-161993.ovf"

"vi://administrator@vCenter40/B

andon, OR/host/Prod/esx3.

wiredbraincoffee.com"

You can see what this import and theresults looked like in Figure 1 (page 13).Here, I used the string to import the

vMA OVF file that I downloaded to avSphere server called “ESX3” managedby vCenter. I specified the datastore andthe name of the VM. I specified that itshould be powered on when the import

was completed. I also specified the user-name (administrator) in the locator. Icould have specified the password butlet the OVF tool prompt me for it. Once imported, the VM was named

with the correct name and powered on(see Figure 2). Again, this is just one of the many

uses of the OVF tool. I could also use itto import an OVF file or other formatinto other VMware virtualization pack-ages like VMware Server or VMwareWorkstation. �

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Figure 2

Once imported, the VM was named and powered on.

IRTUALIZATION haschanged data centers inmany ways. Beyond thereclamation of space,organizations have reduced

power consumption and centralizedmanagement. Many virtualization instal-lations have also moved most of theirdata from local disk resources to someform of shared storage. This increasedreliance on shared storage may be thebiggest impact that virtualization hashad on data centers.By moving all storage requirements

from a large number of underutilizedsystems to a centralized resource such as a storage area network (SAN), organi-zations can consolidate the storageresources and provide centralized man-agement. But these benefits also put anincredible strain on many aspects of atypical data center by a rapid growth instorage consumption. Most organizations that are new to

virtualization may be venturing into theshared storage realm for the first time.For a SAN that absorbs a virtualization

implementation, a number of challengesexist for infrastructure administrators.

INITIAL STORAGE INVESTMENT CHALLENGESMoving all of the storage requirementsfrom individual servers to a SAN is thebest way to implement a virtualizedserver infrastructure, but there is a greatcost associated with this task. Virtual-ized servers are typically huge storageconsumers in many SAN environments. SAN storage is expensive, and connec-

tivity requirements can magnify thecost. In particular, Fibre Channel is anexpensive media for a storage protocolamong all of the switching requirementsas well as host bus adapters (HBAs) oneach server. Storage controllers that provide vir-

tualized storage also include an initialinvestment but can greatly reduce theoverall cost for storage for server virtual-ization installations. With these parame-ters, a potentially large initial storageinvestment may be required up front to

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Critical Decisions for Virtualization StoragePERFORMANCE AND EXISTING INVESTMENTS SHOULD BE CONSIDERED WHEN PLANNING STORAGE FOR VIRTUALIZED ENVIRONMENTS. BY RICK VANOVER

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correctly get started with virtualization.

STORAGE FOR VIRTUALIZATION AND BACKUPSLarge server consolidation projects made possible by virtualization have fundamentally shifted the data require-ments from a large number of relatively

disconnected servers to central storageresources. This creates a series of oppor-tunities for data protection strategies.Although typical backup and restorepractices can be used in virtualizedinfrastructures, there are opportunitiesto be more efficient with data protec-tion.In the simplest scenario, traditional

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VIRTUALIZATION INHERENTLY MAKES disaster recovery easier, but there are certainrequirements that need to be in place to make this possible. One of the more popu-lar routes is to have a fully automated DR product for VMware environments.VMware’s vCenter Site Recovery Manager (SRM) is a turnkey product that workswith 15 top storage vendors to deliver integrated DR. These storage vendors produce storage replication adapters (SRAs) for use

within SRM for various products. The drivers work to coordinate the replication ofdata between the storage systems. One of the key requirements for SRM to work is storage replication. This is

effectively a behind-the-scenes task that copies the VMware datastore contents tothe remote storage system in the DR site. It’s coordinated by the storage controllerto replicate the contents to the remote site. Storage replication to a remote siterequires an investment in bandwidth. Another DR approach in virtualized data centers is to focus on workload protec-

tion. This can be protecting a single virtual machine (VM) at a time through anumber of tools. These tools can require less bandwidth than the storage systemapproach, but it can lack centralized management. Workload protection tools fillthe gap between fully automated DR with storage replication. Products such asVizioncore’s vConverter can protect individual VMs—or physical systems—to anew destination.One option also exists where storage replication isn’t available, yet a fully auto-

mated recovery is required. Novell’s PlateSpin Forge appliance allows organiza-tions to perform continuous physical-to-virtual or virtual-to-virtual conversions onselected systems, creating a protected workload. The Forge appliance can reside ina separate location and allows the protected workloads to be continuously repli-cated to the embedded ESX datastore. Forge can automate the failover for a seam-less experience as well as provide managed failback.

DR FOR VIRTUALIZED DATA CENTERS

agent backups can be passed over infavor of SAN-based solutions. Many cur-rent virtualization-friendly storage prod-ucts allow the centralized data resourceto have a number of protection options.One example is NetApp SnapVault,which provides a disk-based backupsolution on a SAN. This tool takes a lookat the aggregated block-level data for thecontents on disk. In the case of virtualized servers, the

blocks that are examined can span manyvirtualized servers. The SnapVaultengine looks for the differences at theblock level, skipping large blocks thatare unchanged in the protection scheme.The biggest benefit of SAN-based pro-tection is incredibly quick restore times,beyond being a simple and consolidatedview into data protection. Disk-basedbackups and restores will always befaster compared to retrieving somethingfrom tape,Many organizations are going in the

direction of having the SAN storage con-troller fully manage data protection, butthis may not be an approach that allorganizations can support. Bandwidth,off-site retention requirements andexisting investments are obstacles tohaving fully implemented storage-man-aged data protection.

ALL THIS STORAGE ADDS UPAgain, SAN storage is expensive. Butwith this class of storage comes featuresthat can make it pay for itself. One keyfeature is data de-duplication, where theSAN storage controller will look for sim-ilar blocks of data across disks. In lieu ofhaving the same blocks written a largenumber of times on many disks, the con-

troller will manage a single instance ofthese blocks. Virtualization is a perfect match for

de-duplication in that many servers areconsolidated to the SAN and built fromthe same source. Consider a virtualmachine (VM) template, which is howmost virtualized environments deploysystems. As a VM is created from a template to create 10 VMs, those 10machines will not differ much at a blocklevel from each other in many situations.This is especially true for the operatingsystem part of the VMs, even as theybecome patched and updated over theirlifecycle. The benefit here is incredible for vir-

tualization installations because the stor-age requirement can literally be cut to afraction of the raw amount. Some stor-age products that offer de-duplicationeven provide a de-duplication guarantee.NetApp is the current leader in the areaof virtualization guarantees. In this pro-gram, NetApp guarantees that virtualiza-tion installations will need 50% less stor-age than that of the competition. De-duplication benefits are one of the

critical points in planning what type ofstorage to use in a virtualization installa-tion. This approach can be used helpmake a cost model to determine whatproduct fits each requirement. With most SAN systems that have a

front-end controller, there is some levelof initial investment to justify the cost.When selecting a storage platform, it isimportant to determine how many ter-abytes of storage are required for a par-ticular platform. If the virtualization storage require-

ment is only 3 TB, for example, it doesn’tmake sense to invest in a large dual-con-

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troller SAN to get a de-duplication bene-fit that can save a marginal amount ofstorage. If the storage requirement is 15 TB or more, then it would definitelymake sense to make the investment in a SAN that provides additional benefits.

RETHINKING STORAGE PROTOCOLS When it comes to determining a storagesolution for virtualized servers, it isworth a full reconsideration of how stor-age is provisioned. Historically, there are

two main ways to approach storage forvirtualized environments: Fibre ChannelSAN and Ethernet-based storage withiSCSI or NFS. Emerging options willinclude converged networking adapters(CNAs) that can offer 10 Gigabit Ether-net and Fibre Channel over Ethernet toservers. A Fibre Channel SAN has a relatively

high initial investment to create a stor-age fabric. This usually includes a pair of switches and HBAs for each serverconnected to the SAN fabric. Tape

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TOO MANY TIMES data protection in a virtual environment is done the same way asin a physical environment. Although this is an option, there are some efficienciesthat can be realized by going with a virtualization-aware backup and recovery pro-gram. Veeam Backup & Replication is one of the leading complete virtual machine(VM) backup programs that protect VMware virtualized environments. Another popular protection strategy is to use VMware Consolidated Backup

(VCB) to protect VMs. Both of these products use the storage system to protectVMs. In traditional backup and recovery configurations, agents are used on thenetwork to protect VMs. This causes an enormous increase in network trafficwhen servers are consolidated at ratios of 10, 15, 20 or more to a virtualized infra-structure. VM backups using virtualization-aware technologies like Veeam or VCB relieve

the Ethernet network of this traffic. By using a native virtualization feature, a snap-shot, VMs can be protected at additional levels and in a quicker fashion. Simplyspeaking, it is much easier to backup one large file—a VM snapshot—than it is tobackup a large number of small files, such as what would exist on the VM’s file system. VMware environments can take further advantage of built-in efficiencies to pro-

tect VMs with a new feature called Changed Block Tracking (CBT). This featureallows a block of a VM disk file (VMDK) to be analyzed for individual changes onthe larger file. Newer products that use current vStorage APIs, including theVeeam product, can execute quick backups on VMs by using CBT on the individualVMDK files. The CBT feature can also work for replication tools for VMs to addadditional protection, including off-site copies of VMs.

WAYS TO BACK UP A VIRTUAL MACHINE

drives, disk arrays or SAN storage con-trollers would also be attached to theSAN fabric. Fibre Channel has high performance

with speeds of 1, 2, 4 or 8 Gb per second.Fibre Channel storage provides multi-pathing support across the two or moreswitches and the back-end connectivityon storage arrays.The Ethernet-based storage proto-

cols—iSCSI and NFS—can use existingEthernet infrastructure instead of a dedi-cated storage networking equipmentinventory. In most environments, virtu-alization host systems will dedicate anumber of 1 GB Ethernet interfaces tocommunicate to the iSCSI or NFS stor-age. In the case of VMware environ-ments, multiple VMKernel interfaces—driver stack for NFS and iSCSIstorage—would be allocated to multipleGigabit Ethernet adapters to providemultipathing for software-based iSCSIconnectivity.When it comes to deciding which stor-

age protocol is right to use, there is noclear answer. Additional purchase costsand existing investment in storage areusually two critical decision points whenit comes to making a decision about stor-age for virtualization. Many organizations favor an Ethernet-

based storage protocol because thatinfrastructure is usually in place and hasa lower per-port cost than a Fibre Chan-nel SAN. Many organizations also establish tiers

of storage for various workload classifi-cations. For example, development sys-tems may be placed on less expensiveiSCSI storage when top-tier productionworkloads are placed on Fibre Channelstorage.

VIRTUALIZATION AND DISK SELECTIONWhen it comes to selecting storage forvirtualization, decision makers must alsobattle with disk types. Most virtualiza-tion environments choose betweenserial attached SCSI (SAS) and serialATA (SATA) disk types. SAS drives areusually very fast and relatively smallcompared to their SATA counterparts,but they are also roughly twice as expen-sive. Cutting-edge installations can usesolid state disk (SSD) technology forextremely high throughput.Frequently provisioning storage for

virtual environments is a manifestationof what application vendors list in theirrequirements for an application, whichmay or may not include virtualization-specific information. In a virtualizationstorage environment, multiple systemsare aggregated to the same disks throughvarious RAID technologies. Simply speaking, one VM may touch

50 hard drives in a run state. Likewise,one hard drive may provide part of theI/O for 50 VMs. This means that anyapplication requirements need to betaken with consideration for a consoli-dated infrastructure. As environmentspush larger VMs with higher I/Orequirements into production, I/O maybe the new bottleneck. Once a drivetechnology is selected, then the sameperformance arguments can be held onwhat type of RAID technology to usewith overhead taken into account.Storage touches every aspect of a

virtualized infrastructure. The problemis that there is no one-size-fits-allanswer for storage in a virtualized envi-ronment. What is clear, however, is tocarefully weigh options with all factorsconsidered. �

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Stephen J. Bigelow, a seniortechnology writer in the DataCenter and VirtualizationMedia Group at TechTargetInc., has more than 15 yearsof technical writing experi-

ence in the PC/technology industry. Heholds a bachelor of science in electricalengineering, along with CompTIA A+, Net-work+, Security+ and Server+ certifica-tions, and has written hundreds of articlesand more than 15 feature books on com-puter troubleshooting, including Bigelow’sPC Hardware Desk Reference and Bigelow’sPC Hardware Annoyances. Contact him atsbigelow@techtarget.com.

David Davis is a VMwareEvangelist at TrainSignal.com,a leader in video training forIT pros. He holds several cer-tifications, including vExpert,VCP4 and CCIE #9369.

Additionally, Davis has written hundredsof articles and nine video-training coursesat Train Signal. His most popular coursesare the VMware vSphere 4 and vSpherePro Vol 1 video training courses. His per-sonal website is VMwareVideos.com. Follow him on Twitter.

Rick Vanover (VCP,MCITP,MCSA) is an IT infrastructuremanager for Alliance Data, afinancial services corporationin Columbus, Ohio. Vanoverhas more than 12 years of IT

experience and specializes in virtualiza-tion, Windows-based server administra-tion and system hardware. Follow him onTwitter @RickVanover.

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ABOUT THE AUTHORS

Cathleen GagneEditorial Director

cgagne@techtarget.com

Matt StansberryExecutive Editor

mstansberry@techtarget.com

Christine CasatelliEditor

ccasatelli@techtarget.com

Marty MooreCopy Editor

mmoore@techtarget.com

Linda KouryArt Director of Digital Content

lkoury@techtarget.com

Jonathan BrownPublisher

jebrown@techtarget.com

Peter LarkinSenior Director of Salesplarkin@techtarget.com

TechTarget, 117 Kendrick StreetNeedham,MA 02494www.techtarget.com

© 2010 TechTarget Inc. No part of this pub-lication may be transmitted or reproducedin any form or by any means without writ-ten permission from the publisher. For per-missions or reprint information, please

contact Renee Cormier, Director of ProductManagement, Data Center Media,

TechTarget (rcormier@techtarget.com).

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