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Ensuring the Success of VDI Solutions

Although server virtualization is now a common deployment model in data centers, desktop virtualization hasn't caught fire as quickly. But with major vendors like VMware and Microsoft providing virtual desktop infrastructure (VDI) solutions, the trend is quickly moving in that direction. VDI solutions replace traditional desktop and laptop PCs with thin clients, giving users access to applications and services from centrally managed servers in the data center.

For IT organizations, VDI solutions can be easier and more cost-effective to manage and secure than traditional PCs, so why the sluggish adoption rate? One reason is that thin-client solutions of the past--and there have been many--haven't delivered the features and performance that users expect from traditional PCs. Another is resistance to change. PC users don't want to give up the perceived control they have over their applications and data, and IT is understandably reluctant to implement any solution that will degrade performance, frustrate users, and ultimately reduce productivity.

But today's VDI solutions have come a long way from their predecessors, combining the best of thin-client technology with server-side virtualization. For each user, IT creates a customized virtual desktop that resides on a virtual machine (VM) in the data center. Instead of connecting via a dumb terminal to an application on a shared server running a specific operating system (thin-client model), users connect to their own customized, virtual desktops from a range of devices and locations.

The ability to customize virtual desktop images and store them on a VM is a significant distinction and advantage of VDI over previous thin-client solutions. Yet, for all the benefits they can provide--centralized management and control, easier desktop management and recovery, enhanced ability to meet security and regulatory requirements, improved user productivity, reduced OpEx--VDI solutions are, like their predecessors, inherently dependent on the network. That makes them potentially subject to LAN and WAN issues such as network latency, lost connections, and poor performance. These factors alone can be significant enough to kill a corporate VDI initiative because they have a direct impact on user experience and productivity.

For VDI solutions to succeed, then, IT's challenge is to ensure that these solutions perform well and are scalable, reliable, and secure. Not coincidentally, these challenges are common to all network-based applications, and many IT organizations already realize that advanced application delivery controllers (ADCs), which introduce a layer of control into the network, can address these challenges. That's why many network vendors work closely with application providers to develop joint solutions that optimize application delivery over the network.

By intelligently managing traffic, offloading compute-intensive processes from servers, and providing session persistence, ADCs can provide the scalability that's needed for a VDI. Scalable solutions are less susceptible to availability issues, and availability is key to maintaining acceptable performance. Monitoring VDI resources so user requests can be intelligently distributed across all available resources (especially among multiple data centers), improves cross-site resiliency, which in turn improves availability and performance.

VDI solutions offer inherent security benefits because all applications and user data are stored in the data center under IT control. An advanced ADN solution that uses SSL to protect all data exchanged between client and server can enhance a VDI solution, adding stronger security. With the use of new 2048­bit key lengths, however, SSL can consume a lot of server resources, so an ADC solution that intelligently directs traffic and offloads processes from the servers is even more critical to ensure high performance.

While the pros and cons of VDI will likely continue to be debated, organizations that want to move in this direction need to understand that the delivery mechanism--the network--is key to making these solutions successful. Many of the challenges presented by VDI solution can be overcome by placing an intelligent mediator in the form of an advanced ADC between the user and server.

Posted by Karl Triebes on 11/16/2010 at 12:47 PM


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