managing the information that drives the enterprise storage: focus on virtual desktops and storage

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Managing the information that drives the enterprise

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Virtual Desktopsand Storage

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wHEN CONFIGURING STORAGE for a virtual desktop environment, you’ll run into a lot ofthe same issues you had to deal with when you set up storage for your virtualservers. But virtual desktop infrastructure has its own special challenges, alongwith a new vocabulary featuring such colorful expressions as “boot storm” and“linked clones.”

The benefits of virtualizing desktop PCs are pretty straightforward. Youinstantly get more control over operating systems, applications and data thatin all likelihood previously existed in isolation and was left generally unprotected.But the road to realizing those benefits can be a bit bumpy, with your storagesystems having to bear bigger loads—both in terms of capacity and perform-ance—than they’ve likely ever seen.

The numbers can be daunting. If you’re virtualizing 1,000 desktop PCs and theyhad an average of 300 GB of disk each, the shared storage supporting your virtualdesktops may have to provide up to 300 TB of capacity. Of course, sharing somecommon files like operating systems—via linked clones—can knock that totaldown considerably but you’re still going to need a hefty chunk of disk real estate.

Capacity is only half the problem. Shared storage has to have the oomph tohandle hundreds of simultaneous requests, like when the dreaded bootstorm occurs as scores or hundred of users try to boot up and log on at thesame time. That kind of demand can bring a storage system to its knees, andit may take more than just a few minutes for it to recover. And all your userslogging off at the end of the day can have the same effect.

But both of these issues are very manageable. All you have to do is throwmassive amounts of disk capacity at your virtual desktop infrastructure andbeef it up with huge caches and some solid-state storage to boot (literally). Butif you live in the real world—and you don’t have a bottomless budget—you’llhave to approach configuring virtual desktop storage a little more scientificallyand with a little more precision.

The process of configuring VDI storage starts long before any desktops govirtual. You’ll need to understand traffic patterns and have a solid understand-ing of your storage systems capabilities. Rather than a complete overhaul ofthe supporting storage environment, it’s likely that strategic upgrades to theinstalled gear will suffice. 2

Rich Castagna is the editorial director of TechTarget’s Storage Media Group.

Setting up storage forvirtual desktops requiresplanning and perseverance

Copyright 2011, TechTarget. No part of this publication may be transmitted or reproduced in any form, or by any means, without permission in writingfrom the publisher. For permissions or reprint information, please contact Mike Kelly, VP and Group Publisher ([email protected]).

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STORAGE Focus on Virtual Desktops and Storage

ATA STORAGE is no small consideration for any organization thatdecides to implement a virtual desktop infrastructure (VDI).

Taking the VDI approach, an IT department can deliver a full desk-top image to its users from virtual machines (VMs) running on serversin the data center. Ideally, the users won’t notice a difference between

the virtual and traditional PC desktop experience. But the company couldopt for less costly thin-client devices or even repurpose aging PCs/laptopsbecause there’s no need for local storage of the operating system, applica-tions and data.

VDI CONSIDERATIONSDesktop images and user data are stored and backed up centrally, and thepotential demands on back-end systems are not inconsequential, especiallyin a large virtual desktop infrastructure environment.

“It requires an infrastructure build-out to occur in all the other disciplinesof infrastructure,” including servers, networks and storage, said MarkMargevicius, a research vice president at Gartner Inc., Stamford, Conn. “You


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Getting started with VDI:TCO savings at finish line

Data storage is a major consideration fororganizations implementing a virtual desktopinfrastructure, from capacity planning to

performance to costs. By Carol Sliwa

STORAGE


can’t just go forth and say, ‘This is a PC replacement, and it’s only about aPC.’ On the contrary, this is really about building out your data center to support allthose clients.”

Storage costs sit like the solid mass below the water line of an iceberg,Margevicius said, and centralized storage is more expensive than PC-basedstorage. It must also be backed up, he noted.

“Network storage is very important in this virtualized environment,” saidMark Bowker, an analyst at Enterprise Strategy Group (ESG) in Milford,

Mass. “Where many machines are runningon the same physical server for availabilitypurposes and even for mobility purposes,it’s essential to have some type of networkstorage in place so those images can bequickly restarted on a different physicalmachine or easily move between physicalmachines.”

One of the leading virtualizationvendors, VMware Inc., a subsidiary ofEMC Corp., agrees that shared storage isbeneficial in a virtual desktop infrastruc-ture environment, but the company offersno directive on what form that storageshould take. Jon Bock, a senior managerin product marketing, indicated via anemail interview that the company hasseen large virtual desktop infrastructure

deployments in both storage-area network (SAN) and network-attachedstorage (NAS) environments.

“There remains a fair amount of debate in the industry regarding whetherNAS or SAN scales better, including for VDI environments, but no universallyaccepted answer,” Bock wrote. He added that customer’s choices tend tobe driven by their comfort level with managing iSCSI or Fibre Channel (FC)SANs, or block storage, vs. NAS or file-based storage.

VIRTUAL DESKTOP INFRASTRUCTURE CASE STUDY: METRO HEALTHThe storage issues that are more critical in a VDI environment includecapacity planning and management and performance, as illustrated bya case study of early adopter Metro Health, an independent health caresystem serving the greater Grand Rapids area and western Michigan.

On the surface, Metro Health’s VDI effort has produced a number ofbeneficial results. Doctors, nurses and other staff members gain fasteraccess to applications no matter where they are. Fewer users call thehelp desk. IT has improved tools to centrally manage user desktops and toensure information stays secure in the data center rather than on laptops


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“There remains a fairamount of debatein the industryregarding whetherNAS or SAN scalesbetter, including forVDI environments,but no universallyaccepted answer.”

—JON BOCK, senior productmarketing manager, VMware Inc.

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or PCs. Even electricity usage fell, with the elimination of CRT monitors anddesktop PCs.

But Metro Health is still looking for answers on the storage side of theVDI equation, particularly in the area of cost reduction.

When Metro Health launched its VDI initiative two years ago, it found nowhite papers to consult for guidance. The IT group carefully weighed CPUand memory needs and sized its storage environment to accommodate1,500 virtual machine disks of 10 GB each, equipped with Windows XP andthe applications a user might need.

Metro Health soon learned the hard way that it should have taken intoaccount the disk I/O requirements of 1,500 Windows XP desktops, accordingto Chris House, a senior network analyst. Performance suffered wheneverthe user sessions concurrently attempted high disk I/O operations, such asWindows and antivirus updates, because Metro Health’s pair of Hewlett-Packard (HP) Co. EVA 8000 arrays lacked adequate cache to deal with theonslaught of write requests, House said.

To address the problem, Metro Health had to move off the EVAs andexpand its HP StorageWorks XP1024 Fibre Channel SAN arrays by 15 TBapiece. They also had to max out the cache of each one at 50 GB to ac-commodate the VDI sessions and handle the occasional high I/O bursts,according to House.

But the heavy cost of using high-end enterprise storage for VDI is aproblem, and the IT group plans to look into less-expensive alternatives,such as cheaper mid-tier SAN, scale-out systems and local storage ofvirtual machine sessions within its VMware ESX servers, House said.

CONSERVING DISK SPACEAnother option under consideration is the latest version of VMware’s View,which Metro Health sampled previously as part of a private beta test. TheView 3 portfolio includes a new Composer management component thatuses VMware’s Linked Clone technology to create desktop images thatshare virtual disks with a master image to conserve storage space by asmuch as 70%, according to VMware.

In addition, any desktops that are linked to the master image can bepatched or updated by simply updating the master image, with no effectto a user’s settings, data or applications. Because a user’s data and settingsare separate from the desktop image, they can be administered independ-ently, according to VMware.

Chris House, a senior network analyst at MetroHealth, said View 3 couldhelp Metro Health to reduce imaging time from weeks to potentially a fewclicks. Metro Health currently re-images all 1,500 desktops when it needsto push out a Windows service pack update or an important applicationupgrade. The client architecture team spreads the re-imaging over several


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weeks to avoid storage bottlenecks because bandwidth is limited for repli-cation between the XP arrays, which are located in separate data centersin Grand Rapids, House noted.

Antivirus updates now go out at ran-dom times over the course of a week, sothose are no longer a problem, he added.

House recommends that potential VDIusers undertake a pilot project to analyzethe average I/O per second of a block ofactual production desktops and to moni-tor performance during routine tasks,such as patching desktops and installingsoftware. Then, he suggested, they shouldlook for and test arrays that can deliverthe necessary performance, especiallyduring peak I/O times.

“The most important thing to considerwhen planning a VDI deployment is stor-age. You have to size it for performance

instead of just sizing it for capacity,” House advised. “Storage is the No. 1common denominator across the entire environment and if it doesn’tperform well, everyone suffers.”

PLANNING AND MANAGING STORAGE CAPACITY IN VDI ENVIRONMENTSVirtual desktop infrastructure technology is still a work in progress,and capacity planning and management remain among the greatestchallenges confronting any IT department that elects to employ hostedvirtual desktops.

“How much storage do you allocate per user? It’s a very tough questionto answer because what we’re trying to do with hosted virtual desktops isto deliver an identical user experience [to what you] would normally geton a PC,” said Mark Margevicius, a research vice president at Gartner Inc.,Stamford, Conn. “If my PC that I run today in the office has a 120 GB harddrive, are users going to anticipate 120 GB of storage individually—eachand every person? That’s the -dollar question. When I speak to customers,they really struggle with this.”

The latest versions of Citrix Systems Inc.’s XenDesktop and VMwareInc.’s VMware View could alleviate some of the capacity issues withnew features that can limit redundant data, reduce the amount of diskspace needed for desktop images and provision users off the sameimage.


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“The most importantthing to considerwhen planning aVDI deployment isstorage. You have tosize it for perform-ance instead of justsizing it for capacity.”—CHRIS HOUSE, senior analyst, MetroHealth

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THE FUTURE OF VDI ADOPTIONBut Mark Bowker, an analyst at Milford, Mass.-based Enterprise StrategyGroup (ESG), remains dubious about the ROI model for VDI. He said usersare still trying to figure out how to get a return.

“Take a government agency, for exam-ple, where security is a top concern.They’re still willing to implement VDI forthe security advantages,” he said. “But ifyou take a typical corporate environmentthat doesn’t have that same securitychallenge or mandate, maybe there isn’tas much of a compelling issue to deployVDI until the technology continues tomature.”

Gartner claims an organization implementing VDI, or what it refers to as“hosted virtual desktops,” can save between 2% and 12% over the TCO of atraditional PC environment, Margevicius said.

VDI-based desktops account for about 1 million units of the overallworldwide desktop market today. Predictions call for growth to 50 millionunits by 2012, yet that would represent roughly only 5% of the overallmarket, according to Margevicius.

However, Jeff Byrne, senior analyst and consultant with the TanejaGroup, predicted that the innovations from VMware, Citrix and other storagevendors will help make VDI more attractive to more IT organizations andcontinue to render the storage portion of the VDI TCO equation morereasonable.

“Any IT administrator or user who’s read about the storage issues inVDI over the years, particularly up until early 2008, really needs to take afresh new look at what’s happening in this space,” Byrne said. 2

Carol Sliwa is the Features Writer for the Storage Media Group.


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VDI-based desktopsaccount for about1 million units of theoverall worldwidedesktop market today.



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wHEN CONSTRUCTING A VDI PROJECT PLAN, experts and early adopters advise datastorage administrators to start with a pilot or test program to gauge thechanges and costs associated with a virtual desktop infrastructure (VDI).

With VDI storage, desktop operating systems are hosted inside a virtualmachine running on a centralized server. While this makes it easier andcheaper to manage and secure data, it changes the game for storagecapacity, performance and administration.

VDI project plan:Start with right applications

and use pilot programExperts and early adopters say a VDI project plan

demands a different type of infrastructure,and they recommend starting with specificapplications to gauge the effects. By Dave Raffo

STORAGE


Because it requires hundreds or thousands of desktop images to bootsimultaneously, VDI brings about things like boot storms that stress astorage system and often changes the way storage is provisioned, backedup and recovered, replicated and secured.

VDI ADOPTION INVOLVES STEEP I/O DEMANDSThe steep I/O performance issues associated with VDI adoption almostalways require networked storage, but solid-state drives (SSDs) and a largecache are also recommended. However, these technologies bring additional

costs to an organization’s IT infrastructure.“A virtual desktop infrastructure requires

a different style of storage than whatpeople might be used to,” said Ray Lucch-esi, president at Broomfield, Colo.-basedSilverton Consulting Inc. “VDI begs forenterprise-class storage.”

Sam Lee, senior solutions architect atsystems integrator Force 3, said storageI/O becomes a major performance bottle-neck in a typical VDI deployment, andrecommends using SSDs and spreadingthe workload.

A storage system for VDI needs to be able to handle peak I/O for allusers simultaneously at certain times, such as when most users’ log onin the morning or log off at night. Lee said SSDs must also be load-bal-anced for peak efficiency. To run smoothly, Lee said, VDI can requireapproximately 20 to 100 IOPS per desktop during peak times.

“A lot of people vastly underestimate how much I/O a single desktopcan use,” he said. “When you use VMware View or Citrix Provisioning Server,they make a writable snapshot. That’s what a virtual desktop is. Every snap-shot on every desktop reduces space but increases the load on storage I/Obecause you centralize the I/O to one or two LUNs. When you have 150desktops on one LUN, that LUN gets oversaturated.”

According to Lee, “you have to spread it out; you can’t have a single SSDfor 1,000 users. On a Fibre Channel disk, you can probably put three VDIusers per spindle on a 10K drive and five users per spindle for a 15K drive.You can get about 200 users per SSD LUN.”

VDI AND THIN CLIENTS IMPROVE LOG-IN TIMES, CUT COSTSSlumberland Furniture in Little Canada, Minn., has been using virtual desk-tops via thin clients on its showroom floors for approximately seven years,and added its first SAN in late 2006. Slumberland uses Compellent storage


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“A virtual desktopinfrastructurerequires a differentstyle of storage thanwhat people mightbe used to.”

—RAY LUCCHESI, president,Silverton Consulting Inc.

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systems with Cisco Systems Inc.’s Cisco Unified Computing System (UCS)and Windows Terminal Services for thin clients. Seth Mitchell, SlumberlandFurniture’s IT manager, said his VDI farms can require 7,000 to 9,000 IOPS.He expects to add SSDs to the Compellent systems next month, but hasavoided I/O problems by using 10 Gigabit Ethernet (10 GbE) connectivityand spreading the load across enough Fibre Channel drives.

Mitchell said his current setup sup-ports 160 VDI user sessions per server,allowing one administrator to handle1,000 clients while giving sales peopleon the show floor faster access toinformation.

“We have quite a few disks becausewe’re latency sensitive and IOPS hungry,”Mitchell said. “We started with 64 diskson our top tier; now we’re at 80 disks. Weget enough IOPS without any trouble. We

have yet to even make it sweat. Our log-in time is greatly improved withVDI; it used to take 50 seconds to log in, now it’s seven or eight secondsfor a typical user.”

One IT manager for an insurance provider said he migrated over 12,000users globally to Citrix thin clients for a VDI project as part of a data centeroverhaul that included consolidating to three primary data centers fromeight. He estimates the new setup has saved about $10 million so far andprojects future savings of about $50 million.

The insurance company uses EMC Corp. Symmetrix storage systemsand Silver Peak Systems Inc.’s NX-8504 WAN optimization devices toreduce latency. The manager, who asked not to be identified becausecompany policy prohibits him from speaking to the press, said VDI anda good remote access solution makes his disaster recovery (DR) situationeasier to manage.

“One of the benefits we find from desktop virtualization is that I cannow support remote users as if they’re local. I give them a desktop ifthey’re at home or sitting in the airport just like I could if they were inthe office,” he said. “That’s totally changed the way we approach DR. Ican have people work from home instead of bringing them into a tempo-rary DR site or setting up a permanent DR site in a nearby building.”

Still, he doesn’t anticipate moving the entire company to VDI.“We see it as a specialized solution for high-profile users,” he said.

“For the typical rank and file call center people, no, we won’t go to theexpense of rolling out VDI. For people who need a custom programminglanguage or are doing application testing, that’s where we see virtualdesktops.”


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“We have quite a fewdisks because we’relatency sensitive andIOPS hungry.”

—SETH MITCHELL, IT manager,Slumberland Furniture

STORAGE


VDI PROOF OF CONCEPT: WHICH APPLICATIONS ARE BEST FOR VDI?In its “Storage for VDI Buyers Guides: Planning and Considerations &Storage Systems” publication, Broomfield, Colo.-based analyst firm Eval-uator Group Inc. said good candidates for a VDI project plan are salesforce automation (telephone sales, customer service), knowledge work-ers (designers, developers and engineers) and officer workers who sharea standard set of applications.

Many organizations are easing into VDI by piloting it for specific applica-tions or a group of workers who fit one of the above categories.

Brian Diegan, vice president of network services at Hermitage, Pa.-basedFirst National Bank (FNB), said his bank is doing a VDI proof of concept foran application used by its tellers across 300 locations. He expects themost common application for tellers to load within three milliseconds tofour milliseconds vs. the approximately four seconds it now takes. FNBuses VMware for server virtualization, but Diegan said he would probablyuse Citrix for VDI because it makes better use of bandwidth.

“The biggest challenge of VDI is bandwidth for us,” Diegan said. “Wehave 700 tellers, and we have to work through a learning curve with them.We don’t want anything to change for them.” 2

Dave Raffo is the Senior News Director for the Storage Media Group.


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OF ALL THE DATA YOUR COMPANY OWNS, data residing on desktops and laptops is oftenthe least protected. Why? The distributed nature of endpoints makes it difficult tocentralize and consolidate backup, and since desktop/laptop data exists outside theconfines of the data center, backup administrators often don’t see its protection astheir problem.

Virtual desktop infrastructure technology can address this problem by bringingdata that would otherwise live on end-user devices into the data center.

DESKTOP VIRTUALIZATION:BETTER DATA PROTECTION?

Virtual desktop infrastructure technology canease the burden of data protection for laptopsand desktops, but it may not be a good fit for

all types of end users. By Lauren Whitehouse


VDI products enable the centralization of entire personalized end-userdesktop operating environments so that they can be efficiently accessed,managed and protected from a central location. This allows organizations toreduce operational costs, improve service levels, and satisfy compliance andinformation security requirements, all while maintaining an identical—and insome cases, improved—end-user experience.

One caveat is that, as with server virtualization, desktop virtualization willhave an impact on IT infrastructure. Server, storage and networking will allbe impacted. Enterprise Strategy Group (ESG) research shows that nearly two-thirds (64%) of current VDI users have made some form of new storage pur-chase to support their implementation, since data that used to reside onusers’ PCs is stored on data center hardware in a VDI environment. And VDIisn’t a one-size-fits-all solution. Some groups of users aren’t well-suited toit, so different measures should be put in place to protect their data.

DISTRIBUTED COMPUTING’S BACKUP PROBLEMMost IT organizations today give short shrift to protection of PC data. Accord-ing to recent ESG research, only 26% of nearly 500 midmarket and enterpriseIT respondents said that all of their desktop PCs are backed up, and only 18%of organizations back up all of theirlaptops. Furthermore, 24% of respon-dents said they have no data protec-tion process at all for their desktops,and 29% don’t back up their laptops.With desktops and laptops increasinglycarrying business-critical data, theexpenses incurred for a system lossor failure are much greater than sim-ple hardware replacement—most no-tably, lost end-user productivity duringdowntime and more time spent recon-structing lost data.

Many IT organizations take proac-tive steps to centrally administerbackup, ranging from manually copy-ing files to a network share that’s inte-grated in automated server backup processes to directly backing up desk-tops/laptops via server-based backup client agents. The former could creategaps in protection, while the latter introduces challenges due to the sheer vol-ume of devices and the required software licensing to protect them.

Other companies take a different approach, allowing desktop/laptop usersto do it themselves. Users might manually copy files or use a standalonePC-based backup product to automatically back up data to a local storagedevice, such as CD/DVD, USB drive or memory stick. Alternatively, some leveragebackup software-as-a-service (SaaS) to enable automated backup of data to a


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With desktops andlaptops increasinglycarrying business-critical data, theexpenses incurredfor a system lossor failure are muchgreater than simplehardware replacement.

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third-party location. In these situations, copies of corporate data proliferate out-side the custody and control of the IT department (and sometimes the user),potentially introducing additional risk to the organization.

While most IT organizations don’t adequately protect end-user data, thehardware that contains that data is susceptible. With an average hard drivefailure rate of 2% to 4%, a company with 500 laptops could have as many as20 of these devices experience a disk crash. In addition, the portable natureof laptops makes them an easy target for theft/loss and prone to damagefrom being mishandled/dropped.

In spite of these dangers, some IT organizations don’t see the risk of dataloss outweighing the costs of desktop/laptop backup storage capacity andoperational overhead. Moreover, many organizations cite a lack of business orlegal requirements mandating data protection and simply procure, configure andre-image replacement hardware and let users worry about data reconstruction.

VDI’S BACKUP REMEDYVDI enables a user’s complete desktop environments—including OS, profile,applications, user data and customizations—to be deployed as a self-containedpackage, remotely accessible from anywhere. Administrative and managementtasks are, therefore, streamlined and centralized.

While you’re not likely to implement VDI just to solve the PC backup problem(a host of difficult desktop computing challenges are driving its adoption),moving PC images to the data center puts them under the umbrella of thedata center’s data protection policies,processes, infrastructure and operationalstaff, which enables more efficient backupand recovery. And as an integrated compo-nent of server backup, desktop and laptopdata can benefit from advanced featuressuch as data deduplication.

It’s important to note that VDI isn’t asolution for everyone. VDI could be too“locked down” for certain classes of users, such as knowledge workers. Organ-izations generally use or expect to use VDI for distributed workers such as re-mote employees and telecommuters, as well as for task workers in roles suchas data entry and call center (who may require a more limited desktop envi-ronment). And while they’re not ideally suited for VDI because their use of tech-nology extends beyond a traditional set of limited tasks, VDI for knowledgeworkers offers benefits against the leakage of sensitive company information.

However, those user profiles that aren’t a good fit for VDI will remainvulnerable without an alternative desktop/laptop backup strategy. Organizationsadopting an “out of sight, out of mind” attitude regarding endpoint protectioncould leave themselves open to risk. 2

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


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managing the information that drives the enterprise storage: focus on virtual desktops and storage

Technology

vdi storage

virtual desktop storage

storage capacity

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storage environment

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