Dell PowerStore Configuring Volumes

Thin provisioning

Storage provisioning is the process of allocating available drive capacity to meet the capacity, performance, and availability requirements of hosts and applications. In PowerStore, volumes and file systems are thin provisioned to optimize the use of available storage.

Thin provisioning works as follows:

• When you create a volume or file system, the system allocates an initial quantity of storage to the storage resource. This provisioned size represents the maximum capacity to which the storage resource can grow without being increased. The system reserves only a portion of the requested size, called the initial allocation. The requested size of the storage resource is called the subscribed quantity.
• The system will only allocate physical space when data is written. A storage resource appears full when data written to the storage resource reaches the provisioned size of the storage resource. Since provisioned space is not physically allocated multiple storage resources could subscribe to the common storage capacity.

Thin provisioning allows multiple storage resources to subscribe to a common storage capacity. Therefore, it allows organizations to purchase less storage capacity up front, and increase available drive capacity on an on-demand basis, according to actual storage usage. While the system allocates only a portion of the physical capacity requested by each storage resource, it leaves the remaining storage available for other storage resources to use.

The system reports the capacity savings gained from thin provisioning using the Thin Savings metric, which is calculated for volume families and file systems. A volume family consists of a volume and its associated thin clones and snapshots.

Thin provisioning is always enabled.