Use of Logical Unit Numbers (LUNs) With SCSI Disks

You must configure your SCSI disks in your disk controller. A SCSI disk in a disk controller is called a Logical Unit Number (LUN).

z/VSE views SCSI disks as FBA disks. Therefore, for each LUN you must add a corresponding FBA device to your z/VSE IPL procedure, as described in Adding a Disk, Tape, or Printer Device.
Note: An FBA device must not exist in the IOCDS.

You must use a connection path to link each FBA device to a SCSI disk (LUN), as described in Defining FCP Devices, SCSI Disks and Connection Paths to z/VSE.

z/VSE’s SCSI support can use LUNs that have been configured in any of the supported disk controllers.

Configuring LUNs in XIV®, SVC, or Storwize® disk systems:
  • LUNs in XIV, SVC, or Storwize disk systems are represented by decimal numbers.
  • LUNs used in z/VSE are represented by hexadecimal numbers.
  • Each decimal LUN must therefore be translated into a hexadecimal number. A LUN in XIV, SVC or Storwize must be defined in z/VSE as a 2-bytes LUN. For example: LUN number 12 would be translated in z/VSE to LUN=000C or LUN=000C000000000000.