About thin provisioning

ubuntu-serversAlso known as virtual provisioning, thin provisioning is defined as efficient managment of storage space on a SAN. The storage space is allocated on an as needed basis, and many midrange storage systems on the market support this feature. Allocation of storage is acquired when data is written: this requires a system that can serve up storage from a reserved pre-defined storage pool – capacity on demand. Some would think that this process would require greater administrative overhead and managing, but systems can do this type of thing on the fly – automatically. A product that supports this feature that I use in my shop is the EMC Celerra NAS appliance. The Celerra NS-G is a NAS gateway system that uses storage targets located on a CLARiiON CX-3 or CX-4 SAN. Carve out 2Tb on the CLARiiON and allocate it for the NAS, and the the 2Tb array can then be devided up into various file systems. One can then set up dynamic allocation on each of these file systems, if desired, and then assign a certain amount of storage for, as an example, user home directories. When the user home directories start getting full at a 90% utilization of the assigned file system, the NAS will dynamically allocate more storage from that 2Tb pool, usually in 5% increments, up to a pre-defined limit that is set by the administrator.

A green solution, thin provisioning can diminish the amount of powered-on and spinning disks that are sitting idle.