Cutter Project Limited
Virtualized Desktops for Smart Users

What is a Virtualized Desktop?

It's almost thirty years since the PC started to become a common sight in the workplace; a squat box whirring away, delivering applications to the user. Since then it's become ubiquitous. And as things come, so they come to pass: nowadays PCs can be dispensed with entirely using techniques known as Virtualized Desktops or VDI (the I variously standing for Infrastructure or Interface).

In place of the PC your applications run on powerful centrally managed servers shared between users. A small, quiet, low-power device plugs into your network to connect your monitor, screen and keyboard. You get exactly the same applications but at lower cost and using less energy; simple in theory and achievable in practice too.

Many people don't realise just how expensive each PC is. As well as the cost of buying it and replacing it every three to four years, there's also a heavy administration cost involved in backups, keeping antivirus software up to date, maintenance and general management. Figures vary for the exact cost but Gartner Group quote an eye-watering cost (TCO) of between US$5867 and $3413 per year for each PC, dwarfing the initial capital cost.

The 'Virtual' term comes from the idea that in place of a real piece of equipment you now have a Virtual PC all to yourself. Virtualization is a popular technique used in data centres too, where small numbers of powerful servers are used to replace many smaller servers through the use of virtualization software. The fewer servers that are needed, the less space, energy, air conditioning and management resources are involved.

The benefits of a VDI approach are numerous, the most important being

Substantially lower long-term costs, a large part being maintenance and management savings
Reduced overall power consumption
Improved reliability and availability
Improved environmental sustainability from reduced disposal of PCs every 3 to 4 years
The ability to work remotely as easily as on-site

Since you access the software over a network, there's also the opportunity to have the servers located off-site, maybe shared with groups of other organisations doing similar things. In that case there can be innovative models for charging based only on the amount you actually use rather than on ownership of the equipment. This latter approach has attracted quite a buzz-word-rich terminology, generally described as “cloud” computing, or cloud services or similar terms. In its more advanced stages this is more vapourware than reality but it's interesting to contemplate.

In Practice

Virtualized desktop systems really can “deliver the goods” as long as some care and planning is put in first. There are some pitfalls and surprises for the unwary. It would take a much longer article to cover all of them so only the most critical issues will be mentioned here. All of these can be planned-around if the groundwork is done properly.

A careful software audit is needed. Picking the right virtualization technique has a big effect on overall costs; more than one technique may be called for
Some software packages are notoriously ill-behaved in a virtualized setting
PCs used for some specific purposes can't be virtualized: robot control is often an example
Some “power users” need their own PC e.g. heavyweight multimedia editing
Designing fully-virtualized systems needs real care in selecting server size and storage performance. This is easy to underestimate

A typical installation will consist predominantly of virtualized PCs with a smaller number of traditional PCs still used where there is a specific need. This is the smart approach, assuming that everything can be virtualized is unrealistic.

Depending on the users' needs a mix of virtualization methods are likely to be used. Workloads that use mainstream applications may well be able to use low-cost methods such as Microsoft Terminal Services (Remote Desktop Services); this can be highly effective but may not be as seamless as total virtualization, so a small amount of user training may be needed.

Total virtualization techniques will typically be done using one of VMware View, Oracle VDI or Citrix XenDesktop. Each of these delivers effective, scalable and manageable results but naturally each also has its own characteristics and cost implications. The demands that virtualization place on servers and storage requires professional skill to evaluate for proper capacity planning.

The desktop equipment selected also has specific features which may make one more suitable than another for various users. Manufacturers such as Oracle, HP, Wyse, Igel and others all produce suitable desktop devices. For minimum cost it may even be possible to recycle old destkop PCs and press them into use. Support for USB, local printers, specific peripherals and smart cards for user identification and session management will be important parts of the selection process.

The Overall Experience

A well designed Virtual Desktop system can undoubtedly deliver the benefits claimed. Our own and our clients' experiences bear this out. It's easy for poor planning or poor design to deliver unacceptable results and we urge caution in choosing suppliers. Pay close attention to reference sites and check that they are happy with what they have. It's also worth asking searching questions about support, as non-specialist suppliers may initially be able to build a system that works but later have difficulty providing on-demand support from experienced technicians.

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