> # Information About SCSI LUN Discovery

> Small Computer System Interface (SCSI) targets include disks, tapes, and other storage devices. These targets do not register logical unit numbers (LUNs) with the name server.

> The name server requires LUN information for the following reasons:

> - To display LUN storage device information so an NMS can access this information.
> - To report device capacity, serial number, and device ID information.
> - To register the initiator and target features with the name server.

> The SCSI LUN discovery feature uses the local domain controller Fibre Channel address. It uses the local domain controller as the source FC ID, and performs SCSI INQUIRY, REPORT LUNS, and READ CAPACITY commands on SCSI devices.

> The SCSI LUN discovery feature is initiated on demand, through CLI or SNMP. This information is also synchronized with neighboring switches, if those switches belong to the Cisco MDS 9000 Family.

> This section includes the following topics:

> - About Starting SCSI LUN Discovery
> - About Initiating Customized Discovery

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