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.
- Address space remapping *
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
In a block-based storage environment, a single block of information is addressed using a logical unit identifier (LUN) and an offset within that LUN - known as a Logical Block Address (LBA). The address space mapping is between a logical disk, usually referred
to as a virtual disk (vdisk) and a logical unit presented by one or more storage controllers. The LUN itself may be also a product of virtualization in a different layer.
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.