Lessons learned from VDI deployment

22 Nov 2011

Desktop virtualisation comes with a number of challenges, but the benefits of this technology are attractive to any organisation where managing a sprawling desktop estate is a constant challenge to hard-pressed IT teams, as this excerpt from an EMC presentation at IP EXPO 2010 explains.

A virtual desktop infrastructure, or VDI, centralises the creation, deployment, management and support of desktop services into the data centre environment.

That's an appealing prospect for the many organisations where IT teams struggle to to handle a sprawling desktop estate, with all the management time and resources that this task entails.

After all, the average operational cost of a traditional desktop is around $2,000. Provisioning and supporting desktop services is complex and costly. Data protection and compliance present new challenges for desktop use and refreshing desktops to align with new operating systems as they emerge is an added burden. Environmental concerns, meanwhile, cast doubt on the efficiency of traditional desktop PCs and the trend towards agile and responsive It means that systems adminstrators are expected to deliver projects to ever-tighter deadlines.

With a VDI, a single physical server can host a large number of virtualised desktop images. Each image's 'disk' is hosted on an enterprise-class NAS [network-attached storage] or SAN [storage area network] and a 'broker' is used to evenly load-balance client access across the infrastructure charged with supporting desktop services. Meanwhile, connection protocols such as RDP (Remote Desktop Protocol) and PCoIP (PC over IP) are used to access the desktop image over the corporate network. That means that the desktop image belonging to a particular user can be accessed not only from traditional desktops and laptops, but from thin clients and mobile devices, too.

So how does this kind of infrastructure address physical desktop limitations? For a start, a VDI reduces the cost associated with each desktop PC over its lifecycle in the areas of support, administration and break-fix. Fewer staff are needed when the complexity of a desktop estate is reduced by centralising and controlling desktop images in the data centre. At the same time, this means that the dissemination of sensitive corporate data can be protected and monitored and updates can be orchestrated from that central point of control. When it comes to the 'green' debate, meanwhile, VDI allows for the deployment of inexpensive, energy efficient thin clients and, by deploying a range of bespoke images tailored to the needs of different groups of users, IT staff can efficiently meet the demand of users for refreshed desktop images.

In its experience to date with VDI deployments, EMC has learned a number of key lessons that it regularly shares with customers:

1. VDI is not a shink-wrapped solution. There is no such thing as a one-size-fits-all approach.

2. Every company's user environment is different. Reference architectures and generic performance figures can only ever be a guide.

3. The workload of each individual desktop user will vary, even across one organisation. Many organisations contain a range of different user types.

4. Each organisation's desktop services environment will be unique. There could well be, for example, multiple combinations of desktop images, applications and user data.

Understanding the types of applications and user data created inside a company - as well as how that information needs to be delivered to the user and protected - is critical. Are desktop users light or heavy users of services? What kinds of data do they create and store - are they performing basic data input tasks or uploading unstructured content, for example? Does their access to data need to be persistent and what types of devices do they typically use to access it? What type and number of applications exist within our business?

In our experience, successful VDI deployments start small, with careful user profiling, and are then progressed through to a proof-of-concept (POC) to full implementation. Most businesses find that they do not adequately understand the performance required for their desktop images or how large those images need to be - but a failure to balance cost with delivering a good user experience will doom a VDI deployment.

Above all else, organisations need to be realistic about the scope and applicability of VDI. Once it's up and running in the data centre, VDI becomes a Tier 1 application in terms of performance and availability requirements. In order to scale sufficiently, an organisation may need to leverage new technologies such as deduplication, flash memory and thin provisioning. Plus, there remain some unresolved elements to VDI, such as desktop licensing and the general impact on data centre operations that come from centralising desktop access.

But despite the challenges, it is still relatively easy to judge a successful VDI deployment. The IT team should see fewer calls to the helpdesk from frustrated users, along with fewer desk-side visits, less time spent on adds, moves and changes and quicker and simpler application and operating system upgrades. With the right use case and the right cost model, an organisation should be well-positioned to exploit this technology to its fullest effect.