The only real solution to this problem is to move the data, along with the server, to the service provider data center. However, this opens up the challenge of data security. Most IT managers are not yet comfortable with the idea of having sensitive corporate data reside in an external data center beyond their control. And most chief security officers and their teams would balk at the idea.

How are enterprises going to be able to get started with cloud computing? The answer could be for them to begin with virtual clients, instead of virtual servers, as the first step in the journey. Although counterintuitive at first, desktop workloads are actually easier for enterprises to move to the cloud than servers. For starters, cloud-hosted desktops don't require enterprises to move their sensitive data to a service provider cloud. To understand exactly how this is possible, you simply need to think about the architecture of today's corporate desktop.

When desktops were first introduced into the enterprise, they were self-contained entities with both applications and data stored on the local device. However, since the adoption of LAN technology in the '90s, enterprises have increasingly been moving more and more data off of corporate desktops. The reasons for this are clear - centrally storing data allows for easier management and better security, backup, and device mobility, to name a few. Of course, this architecture can introduce a challenge for mobile laptop users who need offline access. However, for most kinds of fixed desktop users, data redirection has become standard operating procedure.

Figure 1: Modern day enterprise desktops access the bulk of their data over a network

Figure 2: When desktops are moved to the cloud, the data remains in the enterprise data center

This trend enables enterprises to shift virtualized desktops to a service provider data center without moving their data. With a cloud-hosted desktop model based on virtual machines, the service provider data center becomes a highly secure, "virtual" branch office of the enterprise. This configuration is enabled through either an existing or newly provisioned private data circuit between the service provider and enterprise data centers. Once this connectivity is established, virtual desktops running in the service provider data center can access network-based resources such as Active Directory, home drives, and the back end of client/server applications the same way existing desktops in the enterprise do. To access their hosted virtual desktop, end users leverage PC remoting technology, such as the ubiquitous Microsoft Remote Desktop Client, and can do so from a wide range of access devices, such as thin or thick clients, re-purposed PCs, laptops, and smartphones.

In addition to solving the data location and security conundrum, there are a number of other benefits that VM-based cloud-hosted desktops offer to enterprises:

• Increased security in branch office scenarios: If enterprises virtualize and centralize physical PCs from remote branch offices with limited or no physical security, they can actually increase the security of those desktop environments. A service provider data center has significant levels of physical security, leveraging best practices such as equipment cages, cardkeys, and even biometrics. This means that cloud-hosted PCs, unlike traditional ones, can't be physically compromised or stolen. In addition, since users interact with their virtual desktops using PC remoting technology, enterprise IT can control whether data can be copied to peripherals attached to access devices. It also means that IT can block malware on USB keys, and other storage devices connected to access devices, from infecting virtual desktops.
• Preserves the rich Windows client experience in the cloud: VM-based cloud desktops provide an uncompromised Windows client experience due to the fact that virtual machines enable the hosting of authentic Windows client OSes, namely Windows XP and Vista. As a result, users can leverage the same standard operating environment used on physical desktops on their cloud-hosted desktops.
• Sustains the existing enterprise IT operating model, while introducing cloud-like properties: Enterprise IT has built its entire client computing operation around Windows. This impacts everything from application development, licensing, and deployment to end-user support and training, as well as many other aspects. VM-based cloud desktops allow enterprise IT to continue with its current operating model while at the same time take advantage of many of the benefits provided by the cloud, such as anytime/anywhere access and subscription economics.
• Separates service provider and enterprise responsibilities: VM-based cloud desktops allow clean separation between the responsibilities of the service provider and the enterprise. This is a function of the hypervisor layer, which creates a clear boundary between the infrastructure powering the VMs and what's inside those VMs. The service provider is responsible for everything up to the virtual machines (servers, storage, virtualization software) and the enterprise is responsible for everything inside the VMs (OS image/licensing, application packaging/licensing and user profiles).
• Supports a combination of on-and off-premise hosting models: It's possible for the virtual infrastructure (VI) powering cloud desktops to be hosted either in a service provider or enterprise data center or both. Think of a private service provider cloud as spanning both environments. If the service provider has connectivity into the enterprise and owns and operates the virtual infrastructure, the solution can be delivered "as a service" regardless of where the VI is hosted. The benefit here is the flexibility of servicing enterprises with different sets of requirements. For organizations with users that are more sensitive to latency (from a remoting performance perspective) or more concerned about compliance, the on-premise hosting model makes a lot of sense. However, enterprises who have very little data center capacity or whose user populations are more distributed may find the off-premise or cloud model more appealing.

As I hoped I've shown, consuming desktops as a service (DaaS) via the cloud is a low-risk/high-reward proposition that enables enterprises to keep their data secure within their own infrastructure while reaping the cloud's cost and flexibility benefits. It also gives enterprises a way to get their feet wet with a cloud approach so they can make smart decisions about whether, when, and how to move server-side applications to the cloud.