"Dynamic volume expansion does not support shrinking the size of a volume," Asaro explained in a recent thin-provisioning report.

Because it does nothing about storage that has been allocated for future use but is idling within an organization, dynamic volume expansion doesn't prevent storage hogging or the tendency among users to overestimate the amount of space needed over a given period of time, Asaro says.

-- Jennifer McAdams

Sidebar: Thin provisioning explained

Sometimes referred to as overprovisioning, allocate-on-write or dedicate-on-write technologies, thin-provisioning options let storage buyers avoid tying up entire pools of capacity immediately.