In computer storage, a logical unit number, or LUN, is a number used to identify a logical unit, which is a device addressed by the SCSI protocol or by Storage Area Network protocols that encapsulate SCSI, such as Fibre Channel or iSCSI.

A logical unit number (LUN) is a unique identifier for designating an individual or collection of physical or virtual storage devices that execute input/output (I/O) commands with a host computer, as defined by the Small Computer System Interface (SCSI) standard.

Aug 6, 2012 · Briefly speaking, you can consider every logical unit (identified by lun) represents a successive logical blocks, numbered from 0. So if SCSI initiator intends to access SCSI target, it must offer target ID, LUN, offset of logical block and how many blocks it wants.

Apr 20, 2012 · The MDs present one IQN for the whole device and each logical disk is presented with a different LUN ID (which is generated/selected when you create a disk-host mapping). The EqualLogic units give each logical disk (volume) a different IQN so they all have a LUN ID of 0.

A LUN is a numeric assignment for SCSI or a Fibre Channel, but a LUN is often associated with a SAN using a RAID system. A standard user will not run into LUN assignments, but administrators working with legacy hardware might find LUN management challenging.

Mar 28, 2023 · The logical unit is a device addressed by the SCSI protocol or Storage Area Network protocols (such as Fibre Channel or iSCSI) that encapsulate iSCSI. LUNs can be used with any device that supports read/write operations, such as tape drives, but is most commonly used to refer to logical disks created on a SAN.

Each SCSI device can contain multiple Logical Unit Numbers (LUNs). These are typically used by sophisticated tape and cdrom units that support multiple media. So Linux's flavour of SCSI addressing is a four level hierarchy: SCSI standards allow …

The post mentions few ways to exactly identify/match the LUN presented from SAN with underlying OS disk. 1. correlating file /proc/scsi/scsi and /sys/block/sd*/device 2. Using sg_map and sg_scan 3. Using multipath commands

LUN (Logical Unit Number) is a unique identifier within a storage device that recognizes logical units, used in the SCSI protocol to differentiate between various storage units on a single device.

May 24, 2021 · Short for logical unit number, LUN is a unique identifier used on a SCSI bus to distinguish between devices that share the same bus. SCSI is a parallel interface that allows up to 16 devices to be connected along a single cable.