Realize that you're moving from a physical desktop environment where you probably weren't managing storage much (if at all) to one where you now have IT resources in a centralized location managing that same capacity on enterprise-class storage. There is no doubt that there are benefits to that in terms of meeting performance requirements, enforcing security, and providing recovery for perhaps critical corporate assets, but there is clearly an additional cost here where there may have been none before.

On top of this, you will be incurring additional management overhead against a baseline storage capacity that can easily be 30-50 percent larger than it was before (when you weren't managing it). Backup is a case in point. You probably weren't backing up your desktop storage before, and it's unlikely that end users were backing it up either. By centralizing it, you can ensure that it is regularly backed up by skilled administrators. You might have had 10TB that you weren't backing up before, and now may have 13-15TB being backed up. You'll need to factor in the additional costs of this secondary storage required to support data protection operations.

At this point it should be pretty clear that you are going to have to do some significant thinking about how you manage storage in your VDI environments if you are going to keep costs under control. Once you have storage under the central control of skilled administrators, there are a number of technologies you can bring to bear to reduce your overall storage requirements. These include, but are not limited to, virtual storage architectures that increase the IOPS per disk spindle by 3x - 10x, storage capacity optimization technologies like thin provisioning and data deduplication that can save up to 90 percent on capacity requirements, scalable snapshots technologies that enable the high performance sharing of common data, and the use of storage tiering to craft the most cost-effective combination of storage technologies to meet performance requirements.

Understanding how best to leverage these storage technologies to minimize the size of the storage configurations needed to meet your VDI performance requirements is the best way to keep your overall storage costs down. And that can go a long way to re-balancing the cost structure so that VDI projects can return a positive ROI.