That requires more than high VM density to keep the ROI positive; it requires changes in IT administration and support to improve processes like change management, provisioning and incident management that don't work effectively within older organizational silos, Staten says. Without the ability to build resource-inventory lists that are more detailed than just the number of physical servers available, IT managers can't intelligently distribute particular VMs or workloads across the available servers, let alone to other data centers in companies that have very far-reaching virtualized infrastructures, Wolf says.

"You start to look at all the resources -- CPU, memory, storage -- as a pool you can allocate," he says. "You can't do that without visibility into all the resources or within existing management silos."

Getting to the point of even automating the provisioning of VMs and putting limits on their resource use, mobility and lifespan requires new management tools that are often limited in scope to just one vendor's software, Staten says.

Getting beyond the first big opportunity for VM stall -- the reorganization of administration and allocation of computing resources means giving sysadmins responsibility for a set of VMs according to the business unit that uses the VMs, or the pertinent applications or other factors, not the physical location of the servers.

Failure to allocate human resources efficiently causes efforts to be duplicated, extra work and gaps in responsibility, all adding up to a huge waste of resources when VMs are floating around without anyone clearly responsible for them.