Over the past 18 months, interest in desktop virtualisation has grown considerably, as organisations look to solve issues around how they manage desktop machines. The biggest challenge for desktop administrators and IT admins has been getting beyond the hype and seeing where their organisations can actually benefit from VDI, desktops as a service or other desktop virtualisation techniques. The corporate idea of “thinking global, acting local” provides the best overall guide on how to make desktop virtualisation work for organisations.

The initial implementations of desktop virtualisation looked at how to solve problems associated with keeping PCs up to date. With patching and application updates leading to staff supporting each machine individually, this added up to a lot of resources dedicated to keeping things ticking over. Desktop virtualisation promised the ability to centralise these machines, making management easier and helping resources to go further.

However, these initial projects faced several challenges, not least of which was the sheer amount of storage within the data centre that was required to make them successful. Instead of each machine having its own storage based on cheap desktop disk drives, the images were now in the centre and consuming much more expensive enterprise-class disk space. This put a hold on the uptake of VDI that we are still seeing affecting pilot programmes and implementations of the technology, alongside other challenges such as personalisation of images and access to resources.

So why are companies still looking at desktop virtualisation, when the challenges are there? Well, the first reason is that the issue of desktop management continues to be significant. Centralising desktops and managing a handful of images rather than multiple individual machines represents such a good opportunity for cost savings that it remains attractive. Secondly, the move to virtualise other IT assets and the potential impact of cloud in the future means that desktop strategies are having to evolve as well.

The technology around desktop virtualisation is also developing at a furious pace to offer ways around the challenges that companies face when it comes to making desktop projects work. Instead of simply applying the same model as server virtualisation, organisations can instead look at the idea of how to keep the best practices that exist around desktop management today, while also benefiting from the additional flexibility and responsiveness that virtualisation can provide.

For most organisations, the choice is between fully centralising all the desktop images, or whether there can be some local processing carried out as well. For example, hosted virtual desktop (HVD) or virtual desktop infrastructure (VDI) models move the entire image back into the data centre, with only the image display and keyboard / mouse data going to and from the user. This means that a variety of devices can be used – from traditional desktop or laptop machines, through to thin client terminals.

While this represents the pinnacle of centralisation, it is expensive to achieve from a server resources and implementation point of view, as more enterprise-class server and storage hardware has to be in place to support users.

Another alternative is to stream the image from the central storage over to the user desktop environment. Rather than having the processing carried out on large enterprise-class servers running a hypervisor layer with all the virtual machines on top, this approach to desktop virtualisation means that while the image is stored centrally, the processing is carried out locally on the user’s machine.

Under this model, any files created or changes to data continue to be stored centrally; however, the fact that images can be run locally on each machine means that an organisations does not need to invest in enterprise-class servers, storage or a hypervisor. This therefore makes this approach more affordable when it comes to capital expenditure.

The image streaming model for VDI does reduce the range of client hardware choices available to the organisation. Thin client or zero client devices cannot be used, as they don’t have the ability to carry out processing locally. However, standard desktop machines are now coming on the market specifically without disk drives installed; this not only makes them more power efficient, but also removes one of the biggest areas for hardware failure from within the device. Organisations can also look at removing hard drives from their existing devices, getting more use out of their existing investments.

One of the biggest challenges for any organisation considering desktop virtualisation is how to manage user settings – this can range from the personalisation that users have carried out on their machines through to what applications, printers and storage resources they are allowed to access. This element of VDI has to be considered as part of any roll-out, as otherwise users will receive a lesser experience when they come to trial virtual desktops for the first time. While users will accept an experience that is the same as they are used to from their traditional desktop, they won’t if it is worse.

It is here that traditional desktop management skills can be used and evolved. Instead of thinking about each desktop as a fixed environment, they can be thought of as ‘workspaces’ that can be more flexible for the user to access. Rather than being limited to a single machine, users can access the same resources from any endpoint in the future.

Desktop virtualisation remains a tantalising prospect for companies looking at how to reduce their costs and improve how desktops are managed. The biggest potential gains will come for those who consider how to apply centralisation to reduce their spending and management overheads, while retaining the feel that comes with individual desktops. Thinking global but acting local applies to both business and desktop virtualisation strategies.