Thin provisioning allows storage administrators to allocate to an application or host an amount of storage capacity that exceeds the amount of purchased capacity in the system. By allowing over allocation of capacity to the application or host, thin provisioning challenges the long-standing practice of having to dedicate capacity upfront based on allocation.

With thin provisioning, administrators can over allocate usable capacity to an application and consume purchased physical capacity as applications write data. Thin provisioning provides storage administrators with the attractive possibility to simplify storage provisioning and increase their storage utilization.