In computer storage, a logical unit number or LUN is an address for an individual disk drive and by extension, the disk device itself. The term originated in the SCSI protocol as a way to differentiate individual disk drives within a common SCSI target device like a disk array. The term has become common in storage area networks (SAN) and other enterprise storage fields. Today, LUNs are normally not entire disk drives but rather virtual partitions (or volumes)of a RAID set.
Nomenclature: In SCSI, LUNs are addressed in conjunction with the controller ID of the host bus adapter, the target ID of the storage array, and an optional (and no longer common) slice ID. In the UNIX family of operating systems, these IDs are often combined into a single "word". For example, "c1t2d3s4" would refer to controller 1, target 2, disk 3, slice 4.
(Logical Unit Number) is an identification scheme for storage disks that typically supports a small number of units addressed as LUN 0 through 7, 15 or 31 depending on the technology. For example, Fibre Channel supports 32 addresses (0-31). A LUN may refer to a single disk, a subset of a single disk or an array of disks. Derived from the SCSI bus technology, each SCSI ID address can be further subdivided into LUNs 0 through 15 for disk arrays and libraries. See SCSI.
Logical Unit Number Masking or LUN masking is an authorization process that makes a LUN available to some hosts and unavailable to other hosts.The security benefits are limited in that with many HBAs (i.e. say, SCSI cards) it is possible to forge source addresses (WWNs/MACs/IPs). However, it is mainly implemented not as a security measure per se, but rather as protection against misbehaving servers from corrupting disks belonging to other servers. For example, Windows servers attached to a SAN will under some conditions corrupt non-Windows (Unix, Linux, NetWare) volumes on the SAN by attempting to write Windows volume labels to them. By hiding the other LUNs from the Windows server, this can be prevented, since the Windows server does not even realise the other LUNs exist.
Nomenclature: In SCSI, LUNs are addressed in conjunction with the controller ID of the host bus adapter, the target ID of the storage array, and an optional (and no longer common) slice ID. In the UNIX family of operating systems, these IDs are often combined into a single "word". For example, "c1t2d3s4" would refer to controller 1, target 2, disk 3, slice 4.
(Logical Unit Number) is an identification scheme for storage disks that typically supports a small number of units addressed as LUN 0 through 7, 15 or 31 depending on the technology. For example, Fibre Channel supports 32 addresses (0-31). A LUN may refer to a single disk, a subset of a single disk or an array of disks. Derived from the SCSI bus technology, each SCSI ID address can be further subdivided into LUNs 0 through 15 for disk arrays and libraries. See SCSI.
Logical Unit Number Masking or LUN masking is an authorization process that makes a LUN available to some hosts and unavailable to other hosts.The security benefits are limited in that with many HBAs (i.e. say, SCSI cards) it is possible to forge source addresses (WWNs/MACs/IPs). However, it is mainly implemented not as a security measure per se, but rather as protection against misbehaving servers from corrupting disks belonging to other servers. For example, Windows servers attached to a SAN will under some conditions corrupt non-Windows (Unix, Linux, NetWare) volumes on the SAN by attempting to write Windows volume labels to them. By hiding the other LUNs from the Windows server, this can be prevented, since the Windows server does not even realise the other LUNs exist.
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