To quote Joni Mitchell's lyrics to Big Yellow Taxi, sometimes you really don't know what you've got till it's gone. This sentiment could well apply to many organisations that followed the move to client-server architecture in the 1990s. Although client-server computing provided greater flexibility to end users, the terminal era that preceded it had one significant advantage - centralised control. By distributing computing resources out to the end user, IT managers also distributed their problems.
United States software company Citrix went some way towards providing a compromise with its Presentation Server software (now renamed XenApp), which streamed a complete desktop from a server to a remote desktop or thin client, allowing centralised control of application management, even within a PC-based environment. Microsoft subsequently adopted the technology as Windows Server 2003 Terminal Services.
But in effect, this solution involved locking down the user's desktop, and has not always proved suitable for all applications in all environments.
The realisation by many technology leaders that they were perhaps foolish to give up centralised control has seen the industry respond with another solution. Rather than streaming a standard desktop image from a single template to remote users, IT professionals asked themselves whether they should virtualise the desktops, store the user's entire desktop configuration centrally and stream the whole thing to the end user.
Just as many companies have now embraced virtualisation technology as a means of consolidating numerous physical servers onto a small number of more powerful devices, many are now consolidating their desktop environments into virtual desktops.
This enables the user to enjoy a personalised desktop experience, displayed on any suitable device, including thin clients, rather than just on a PC. The IT department has the security of knowing that should anything go wrong, the entire desktop image is resident within the data centre, and the desktops can then be created or erased at will.
The Western Australia-based materials handling business United Equipment is using desktop virtualisation to take control of its desktop environment as it expands. The company was formed in early 2005, when various enterprises came together to form a single entity with operations across Australia.
United Equipment's network administrator, Santosh Majety, says the company has operated a centralised control model since its formation, based on Wyse thin-client terminals. All end-user data and applications are consolidated into a data centre, and as United Equipment acquires new companies, their desktops are also transferred to and served from the data centre.
"It's still a growing company, so we didn't want to have a decentralised environment with the data all over the place," Majety says. "That would be difficult for us to manage and administer."
The company had been running Windows Terminal Services, but was facing numerous performance issues, in particular relating to one of its enterprise resource planning applications. United Equipment initially deployed 100 virtual desktops and has expanded to 250, using VMware's Virtual Desktop Infrastructure (VDI) software.
National ICT manager for United Equipment, Sharen Cameron, said features VMware provided, such as server consolidation, disaster recovery and resource distribution and mobility, had already helped the company reduce server sprawl. So it made sense to extend the technology to the desktop environment.
Majety reports an immediate 30 per cent performance improvement in the enterprise resource planning system, and says end users are benefiting in other ways.
"With Terminal Services, we had locked [the desktop] down completely and they couldn't do anything," Majety says. "But with VDI, we have lent them some flexibility in doing things."
United Equipment has created a disaster-recovery process through which users are switched across automatically to active back-up units should anything happen to the host servers, which carry about 50 virtual desktops each. Majety says the company is looking at an off-site back-up strategy, and expects to add up to 100 more desktops to its virtual environment as it expands this year.
Although United Equipment has been able to standardise around a single technology, the decision of which to choose is testing many IT managers. VMware's VDI is the most established in terms of desktop virtualisation but Citrix has recently released its XenDesktop and Microsoft is introducing a virtualisation service as well.
There is also the option of virtualising only certain applications. The evolution of Citrix's XenApp offers this model and Australian company NetLeverage has a similar solution. It allows a company to serve multiple desktops from the same instance of an operating system, rather than running one for each desktop, as occurs in desktop virtualisation.
Capture and cache
The pros and cons of desktop virtualisation are many, although problems appear to be solved as soon as they are identified.
Although a virtual desktop provides greater management control to the IT department, and retains the capacity for the user to customise applications and interfaces, it is inaccessible to users offline.
But new forms of virtualisation allow users to capture and effectively cache applications on their desktop, continuing to work with them even when they are offline. Entire desktop clients can also be stored as flat files on USB drives and accessed from any computer.
Queensland-based technology services provider SPARQ Solutions is evaluating these choices. SPARQ is the shared IT services provider for Queensland energy distributors Energex and Ergon Energy, and is running 75 virtual desktops based on VMware's VDI software. Its virtual desktop farm is mainly for its IT support group; some are being used for application testing within the business.
The company's number of virtual desktops will probably grow to 150 during 2008-09. It is also virtualising 350 servers using VMware Windows.
SPARQ IT infrastructure manager Brett Hart says an early benefit is that staff can gain simultaneous access to multiple machines in different IT environments.
"Energex, Ergon Energy and SPARQ run separate Windows domains, and some of our developers and service-desk staff need to get onto a machine that sits in that particular domain," he says. "They are able to do that without having three or four machines sitting on the desk. They just connect into one of these virtual machines."
They can also launch and roll back to different versions of the desktop.
"Our packaging team, which packages applications to be deployed to the clients, has a significant portion of these virtual desktops," Hart says. "They connect to these desktops, test the application packaging and deployment process, and then have the ability to restore the desktop to its previous state.
"Before, they would have to rebuild workstations to get them back to a clean state, which was time-consuming and costly. Now it is done pretty much instantaneously."
A balancing act
Hart says a major consideration in being able to create desktops so easily is that policies and procedures must be sufficiently robust to control costs.
"There is a perception that these systems are free because you can launch them so quickly, but they are certainly not free," he says. "It puts greater onus on having financial models in place that allow you to apportion costs for services based on PC and server numbers."
But when it comes to deploying applications and desktops to SPARQ's clients, Hart says he is philosophically in favour of providing greater flexibility to end users. "Pulling desktops back to the data centre provides greater control from an IT perspective, but I think we need to balance that with allowing people to make changes to their environment," he says.
However, he concedes that like many others, he is somewhat baffled by the variety of technology choices emerging.
"It is a challenge to see through the minefield," Hart says. "We have quite a significant Citrix farm, with 130 Citrix servers, and they are used for presenting applications to users. VDI technology is all about getting things in front of users, but we have a large notebook fleet, and VDI doesn't fit in all that well with offline work."
SPARQ is also trialling Citrix XenDesktop software. Hart has yet to receive feedback but is intrigued by application-level virtualisation and streaming.
"Being able to launch an application on the desktop, and when you disconnect, have the features that you are using continue to work, would fit well with our mobile fleet," Hart says.
"Our next step is to look at products that are out there and develop a strategy. There is value in getting VDI out to the clients, but in order to control costs, I want to be sure that we don't end up with a sprawl of different technologies."
Information technology services provider Convergence e-Business Solutions prides itself on being able to deliver IT to some of the most difficult locations, where poor communications, limited skills and tight budgets are the norm.
For the past 18 months, the company has been working with community-controlled Aboriginal health services in central and northern Australia, covering 30 different services extending from the far reaches of east Arnhem Land to the borders of Western Australia and South Australia.
It has been working with NetLeverage's application-virtualisation technology to deliver secure applications.
"You've got poor quality communication systems, you have low-level support and maintenance systems, and you have information that is quite critical," technical specialist Tom Cordingley says.
"And you have distributed services looking after groups of people that move between communities. So you need online services for them to work."
The company had trialled other methods, including deploying applications using Citrix Presentation Server over ISDN links, but this proved ineffective. It was attracted to NetLeverage by the quality of its application delivery over low-bandwidth connections and a cost-saving over virtualisation systems in server hardware, as the process streams only applications - consuming fewer resources than streaming an entire desktop.
"You can maintain secure environments within single instances of your Windows desktop, rather than deploying a single desktop for each user," Cordingley says. "And if you can get three or four users per desktop, it is costing you a third the amount of hardware. You also require fewer patches and upgrades when you install newer software."
One community health service operates eight locations across the northern part of South Australia - ranging from sophisticated clinics to basic facilities - and services a highly mobile population.
Each facility needs to be able to access the same health records for each patient, however, with an accompanying requirement for individual privacy.
Although some sites are connected via ADSL, Cordingley says two rely totally on satellite links. The resulting latency issues can be fatal for some virtualisation systems, but Convergence principal Alistair Muir says this has not been a problem on NetLeverage. The applications are stored at Sydney data centre AC3, ensuring security and privacy.
"We are now able to deliver any system over any telecommunications infrastructure," Muir says.
"This stuff will run over a dial-up link. If we can get an internet connection, we can provide people with secure access to their health records.
"That means no VPNs, application accelerators or other expensive stuff."
Cordingley says the next step is to move the service's mail systems onto NetLeverage, and then some of the additional desktop applications, as there are no back-up or storage facilities at the remote sites.
"Our major battle is to reduce the complexity of technology at the remote end. What we really want to get it down to is a router and half a dozen thin clients."
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