Storage virtualization refers to the process of abstracting logical storage from physical storage. The term is today used to describe this abstraction at any layer in the storage software and hardware stack.
Virtualization of storage helps achieve location independence by abstracting the physical location of the data. The virtualization system presents to the user a logical space for data storage and itself handles the process of mapping it to the actual physical
The virtualization software or device is responsible for maintaining a consistent view of all the mapping information for the virtualized storage. This mapping information is usually called meta-data and is stored as a mapping table.
The address space may be limited by the capacity needed to maintain the mapping table. This is directly influenced by the granularity of the mapping information.
The virtualization software or device uses the meta-data to re-direct I/O requests. It will receive an incoming I/O request containing information about the location of the data in terms of the logical disk (vdisk) and translates this into a new I/O request
to the physical disk location.