SCSI_ID(8)		 Linux Administrators Manual		   SCSI_ID(8)



NAME
       scsi_id - retrieve and generate a unique SCSI identifier

SYNOPSIS
       scsi_id [options]

DESCRIPTION
       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 output, 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 assume black listed, the -g 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:


       # scsi_id -p 0x80 -s /block/sdg
       SIBM	3542	       1T05078453


       Identifiers based on page 0x83 are prefixed by the identifier type fol
       lowed 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):


       # /sbin/scsi_id -p 0x83 -s /block/sdg
       3600a0b80000b174b000000d63efc5c8c



OPTIONS
       subsystem
	      Deprecated method: when called with only a single argument with
	      out  a  leading -, runs in a hotplug mode, and expects the envi
	      ronment variable DEVPATH	to  specify  the  corresponding  sysfs
	      device. See section below on usage with udev.

       -a     Always  print  information  (model,  vendor  strings)  about the
	      device even if it does not support VPD pages.

       -b     The default behaviour - treat the device as black listed, and do
	      nothing  unless  a  white  listed device is found in the scsi_id
	      config-file.

       -d device
	      Instead of determining and creating a device  node  based  on  a
	      sysfs  dev  entry  as  done  for	the -s, send SG_IO commands to
	      device, such as /dev/sdc.  This argument	should	also  be  used
	      when  invoked via udev to avoid problems with creation of tempo
	      rary files on not-yet writable directories.

       -f config-file
	      Read configuration and black/white list entries from config-file
	      rather than the default /etc/scsi_id.config file.

       -g     Treat  the  device as white listed. The -g option must be speci
	      fied on the command line or in the  scsi_id  configuration  file
	      for scsi_id to generate any output.

       -i     Prefix  the identification string with the  driver model (sysfs)
	      bus id of the SCSI device.

       -p 0x80 | 0x83 | pre-spc3-83
	      Use SCSI INQUIRY VPD page code 0x80, 0x83, or pre-spc3-83.

	      The default behaviour is to query the available VPD  pages,  and
	      use page 0x83 if found, else page 0x80 if found, else nothing.

	      Page  pre-spc3-83 should only be utilized for those scsi devices
	      which are not compliant with the SPC-2 or SPC-3 format for  page
	      83.   While  this option is used for older model 4, 5, and 6 EMC
	      Symmetrix devices, its use with SPC-2 or SPC-3 compliant devices
	      will  fallback to the page 83 format supported by these devices.

       -s sysfs-device
	      Generate an id for the sysfs-device.  The sysfs mount point must
	      not  be included. For example, use /block/sd, not /sys/block/sd.

       -u     Reformat the output : replace all whitespaces by underscores.

       -x     Export all data in KEY= format used to  import  in  other
	      programs.

       -v     Generate verbose debugging output.

       -V     Display version number and exit.


USAGE WITH UDEV
       If scsi_id is invoked with one argument without a leading -, it assumes
       it is called for a hotplug event, and looks for the sysfs device in the
       DEVPATH	environment  variable.	This mode is deprecated, but available
       for backwards compatibility.

       If the DEVPATH environment variable is set, scsi_id assumes it has been
       invoked	via  udev  (or	some other hotplug program), and all errors or
       warnings are sent using syslog.

       To determine the specific value needed in a  RESULT  key,  use  the  -s
       option, for example:


       /sbin/scsi_id -s /block/sda


       scsi_id is one of the tools used in the "Linux Persistent Device Names"
       scheme that creates persistent device links in /dev/disk. It is	called
       with  the  -x option which will print all values in a defined format to
       let udev import it into its own environment for later event processing.

       An  example  custom  udev  rule	using  scsi_id, that will name a block
       device and any partitions for the device matching the scsi_id output of
       312345:


       BUS=="scsi", PROGRAM=="/sbin/scsi_id -d %N -s %p", RESULT=="312345", NAME="disk%n"



FILES
       /etc/scsi_id.config		    configuration and black/white list entries


SEE ALSO
       udev(7)

AUTHORS
       Developed  by  Patrick  Mansfield  based on SCSI ID
       source included in earlier linux 2.5 kernels, sg_utils source, and SCSI
       specifications.



				 December 2003			    SCSI_ID(8)