Thin Provisioning and Reclamation
One of the toughest challenges of storage management is to decide how much storage space is needed for a computer or application. If you allocate too little you may run out of space, too much and you waste valuable storage resources by tying it up to one computer.
Thin Provisioning is a fundamental capability of BeyondRAID, allowing you to allocate the right amount of storage for today, while allowing you to expand capacity by just adding a drive to the Drobo or replacing an existing drive with a larger one.
With Drobo, this expansion is nearly instant and occurs when a new or larger drive is inserted without any disruption in service. If you are running low on space, all you need is another hard drive to add to the Drobo. Adding more drives instantly increases usable storage capacity.
Adding additional drives instantly increases usable storage capacity, in this case, from
1.5 TB to 2.5 TB (assuming single disk redundancy).
While 4- and 5-bay Drobos often contain one thinly provisioned 16 TB volume, 8- and 12-bay models allow for user-controlled volume creation. These volumes (or LUNs) are called Smart Volumes™ and they pull needed storage from a common pool (thin provisioning) and then return deleted blocks back to the common pool (thin reclamation), preventing free space from being tied up by any particular server.
As volumes consume storage, they pull from a common pool of free space and when
storage is freed up, it is relinquished back to the same pool.
Space allocation is automatically managed, which helps maximize storage resources. You can try this out for yourself. If you have a large file on a volume and then you delete it, you will see the free space of the Drobo grow, making that freed up space available to any other volume. Even enterprise-class arrays with thin provisioning do not return consumed storage back to a common pool at this granular of a level.