Get/retrieve/display “UUID” of the scsi device using “scsi_id” command

To Retrieve/display the UUID of a scsi device we can use “scsi_id” command ..

The output of the command shows the UUID of the device. UUID is unique so it is used as primary key to the device. Also, these identifiers are persistent across reboots

 

For ex: To retrieve UUID of my ‘sda’ device I used below command.

[root@humbles-lap ]# scsi_id -g /dev/sda

350024e9003a0e80d

 

This “scsi_id” can be used in a SAN environment. That said, this command can retrieve the UUID of the lun ( scsi device) in host system. “scsi_id” man page give more information on this.

 

–snip–

 

scsi_id queries a SCSI device via the SCSI INQUIRY vital product data (VPD) page 0x80 or 0x83 and uses the resulting data to generate a value that is unique across all SCSI devices that properly support page 0x80 or page 0x83. If a result is generated it is sent to standard output, and the program exits with a zero value. If no identifier is out‐ put, the program exits with a non-zero value. scsi_id is primarily for use by other utilities such as udev that require a unique SCSI identifier. By default all devices are assumed black listed, the --whitelisted option must be specified on the command line or in the config file for any useful behaviour. SCSI commands are sent directly to the device via the SG_IO ioctl interface. In order to generate unique values for either page 0x80 or page 0x83, the serial numbers or world wide names are prefixed as follows. Identifiers based on page 0x80 are prefixed by the character 'S', the SCSI vendor, the SCSI product (model) and then the the serial number returned by page 0x80.

For example: # /lib/udev/scsi_id --page=0x80 --whitelisted --device=/dev/sda SIBM 3542 1T05078453

Identifiers based on page 0x83 are prefixed by the identifier type followed by the page 0x83 identifier. For example, a device with a NAA (Name Address Authority) type of 3 (also in this case the page 0x83 identifier starts with the NAA value of 6):

# /lib/udev/scsi_id --page=0x83 --whitelisted --device=/dev/sda 3600a0b80000b174b000000d63efc5c8c

 

–/snip–

Hope it helps..

 

 

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