What Does Virtual Logical Unit Number (Virtual LUN) Mean?
A virtual logical unit number (virtual LUN) is an identifier for a storage area not directly linked to a physical disk drive or set of drives. A traditional LUN corresponds to a physical hard disk or storage device. By contrast, virtual LUNs are labels for virtual storage spaces or partitions from one or more hard disks.
Techopedia Explains Virtual Logical Unit Number (Virtual LUN)
In general, virtual LUNs are used for different kinds of storage area networks with storage systems like SCSI or fiber channel setups. The fact that these storage identifiers are not linked to a specific physical hard disk makes them more versatile in many ways. In fact, one of the basic ideas behind virtual LUNs is that administrators can allocate smaller amounts of storage space across one or more hardware locations. That’s why some call a virtual LUN a thin LUN or refer to its use in thin provisioning, where storage spaces are set up according to more conservative estimates of user needs, rather than according to heavier projected demands for storage space. The end result of some thin provisioning strategies is that less storage space goes unused.
Another way to use virtual LUNs is to provide fault tolerance by writing data across more than one hard drive or desk. These new systems help with enterprise resource planning and data backup/recovery strategies.