The concept behind VDI is to centralize desktop operating systems, applications and data in the data center. Desktop operating systems and applications run in virtual machines (VMs) on data center servers, but users access the "virtual desktop" and applications from a thick or thin client through remote display software. Individual users' virtual desktops are isolated from each other -- if one virtual desktop goes down, it doesn't affect other virtual desktops. Data may also be stored centrally on networked storage.
VDI creates efficiencies for hardware and resource utilization, and the associated power costs. Similar to server virtualization consolidation ratios, multiple virtual desktops can run on a single physical system. The operational overhead related to deployment, upgrades, patch management, trouble-shooting/resolution, moves/adds/changes and data protection of distributed PCs are trimmed with a centralized strategy.
With VDI, virtual desktops run on servers with high-availability features that protect against downtime. In the event of an unplanned outage, desktops can be quickly recovered by deploying a new virtual desktop to a user.
Backup and disaster recovery of virtual desktops that leverage shared storage is simplified and centralized, and backup network traffic is eliminated. Data protection solutions in the data center -- such as backup, snapshot and continuous data protection (CDP) -- can be used to protect virtual desktops. Typical client/server backup of virtual desktops may prove too burdensome on the host's shared resources. Setting up staggered backup schedules and policies for each virtual desktop can resolve this. Client-based data deduplication can also provide a possible answer to the burden placed on system resources. Data deduplication identifies and eliminates redundant virtual desktop data that's transferred and stored. Because a full backup requires data to be read and pushed out to the backup engine, deduplicating data within a virtual desktop and across virtual desktops will significantly reduce the strain on shared resources and applications, as well as the amount of data copied and stored.
By capturing virtual desktops via snapshot technology, for example, the complete state of the desktop is protected. This also enables multiple recovery options, including physical-to-virtual, virtual-to-physical and virtual-to-virtual.
CDP for files technology automatically and efficiently keeps copies of files, maintaining multiple versions of the file (i.e., the virtual desktop image). Multiple versions of the virtual desktop image make it possible to roll back to a previous image (to undo changes from a patch, to recover from corruption, or even to go back to a previous version of a file contained within the image).
So what are the potential drawbacks of VDI? For starters, the technology is in its infancy, so application integration/support may be a problem. Initial deployment may take longer and support organizations have to readjust processes. Also, this approach may not be suited for every organization or user. VDI could be too "locked down" for certain classes of users and performance issues may interfere with the pace of work for others. Another deterrent may be the acquisition and deployment costs. However, the investment may be justified over a multi-month period as organizations realize other benefits and savings. Organizations that successfully implemented other virtualization strategies such as server and application virtualization and benefited from its cost savings and business continuity benefits may be more likely to adopt VDI. Users of server virtualization recognize that the infrastructure can be further leveraged to provide centralized management, security and the administration of desktop images, especially in regulated industries with stringent compliance requirements. And the availability and data protection benefits are a nice bonus.
About the author: Lauren Whitehouse is an analyst with Enterprise Strategy Group covering data protection technologies. Lauren is a 20-plus-year veteran in the software industry, formerly serving in marketing and software development roles.
This was first published in May 2008