If virtualization has proven anything over the past decade, it's that enterprise systems don't exist in isolation. Even in the pre-virtual days, during the silo period of fixed hardware/software relationships, changes in one set of resources could greatly affect systems elsewhere, although the consequences tended to be limited in scope.
So now that desktop virtualization is upon us, inquiring minds are naturally wondering how VDI is likely to alter the delicate balance that has arisen in virtual server, storage and networking infrastructure.
The answer, it seems, is quite a bit. In fact, you could argue that overcoming the challenges in coordinating centralized virtual resources was just a warm-up compared to what lies ahead in the desktop architecture.
Naturally, VDI's biggest impact will be felt in storage networking. As SymQuest Group's Matt Prigge pointed out recently, virtual desktops will require additional storage capacity, particularly if you are dealing with rich media files. But scaling up capacity as a relatively cheap and easy process compared to increasing your IOPS capability to handle higher transactional loads. Virtual desktops will also require more transactional disk resources, both during boot-up and normal operations.
In fact, for data like disk file images, particularly those that are shared across hundreds of users, it might not be a bad idea to ditch the SAN altogether in favor of the VM's own local host server, according to tech blogger and author Brian Madden. This will require server-mounted disk drives, but you could still get eight or more 15k SAS drives for less than the cost of a Fibre Channel HBA and all the related SAN equipment. Save your full SAN for non-disposable files and application data.
It's also important to recognize that VDI is arriving right at the moment when the desktop is losing its perch as the medium of choice for users to interact with data. The rise of smartphones and other mobile gadgets means that any VDI system will have to accommodate multiple access mechanisms, says The 451 Group's Dan Kusnetzky. In the end, the very notion of a desktop application might give way to Web applications, which can be more easily tailored to a variety of user devices.
Any way you look at it, VDI is a much more challenging prospect than server or I/O virtualization simply because it represents a much more radical change for users. As Gartner analyst James Browning explained to my colleague Ann All recently, virtual technology has been largely transparent to the user so far, but now that VDI is bringing real change to the computing experience, expect to hear a fair amount of blowback from those who like things the way they are.
Despite these concerns, desktop virtualization represents the next major gain in data center efficiency. Not only does it allow you to further leverage the virtual infrastructure already in place, but it can greatly reduce operational costs, particularly energy consumption, compared to current desktop infrastructure.
But like anything else IT-related these days, it has to fit comfortably within the larger enterprise ecosystem.