Provided by: scsitools_0.12-3ubuntu1_amd64 bug


       scsidev  -  populate  /dev/scsi  with  device  names  that  are  persistent  against  SCSI
       configuration changes.


       scsidev [ -f ] [ -n ] [ -d ] [ -l ] [ -L ] [ -m mode ] [ -c mxms ] [ -A aliasfile ] [ -r ]
       [ -M ] [ -e ] [ -o ] [ -s ] [ -v ] [ -q ] [ -h ]


       scsidev  is  a utility that is used to guarantee that the same device node can be used for
       the same scsi device, no matter what other scsi devices are added or removed from the scsi
       chain.   The  need  for this tool arose because device numbers are assigned dynamically at
       boot time, and if a new disk were added to the system (or if some disk  didn't  spin  up),
       then  fixed  device  nodes  would cause the wrong filesystems to be mounted, checked, etc.
       This can also result in security holes, as some device nodes  may  have  permissions  that
       allow  general  users  access to the raw device, and if the mappings were to change, users
       would be able to access different devices.

       scsidev is designed to be used once each time the system boots.  It will scan all  of  the
       detected  devices  on  the  system, and determine a immutable name that will represent the
       device.  It first checks to see if a node by this name already exists -  if  this  is  the
       case,  then  it  checks to see if the major/minor numbers are correct.  If a change in the
       minor number is required, then a new  device  is  created  with  the  correct  major/minor
       numbers,  and in addition, any ownership and permissions for the old device are applied to
       the new device.

       Once this process is complete, then scsidev will scan all of the entries in the  /dev/scsi
       directory,  and see if any of them are for devices nodes which were added for devices that
       are not active.  The permissions of inactive devices are stored in a .shadow. file and the
       device  node  is removed as a security precaution, since these might have permissions that
       would allow people to access devices that they should not be able to access.  This is  the
       default  behaviour  and  is considered ideal for most cases, as it preserves the ownership
       and permissions of the files and is secure.

       The so called sanitizing can be influenced by the options -f -d -n.

       When you rescan the bus by using  the  script  or  manually  by  using
       commands like
       echo "scsi add-single-device C B T U" >/proc/scsi/scsi
       (C  = Controller (host) no., B = Bus (Channel), T = Target (SCSI ID), U = Unit (SCSI LUN))
       after the system is booted, then you will have to rerun scsidev so that the  device  nodes
       for the newly detected devices are properly updated.

       The  device  nodes  that  scsidev creates look something like "sdh4-334c0i0l0p1".  In this
       case, the various components of the name represent physical attributes about the device or
       the  host  adapter to which it is connected.  To begin with, the "h4" indicates that it is
       connected to an Adaptec 1542.  The "-334" is a means of identifying which 1542 the  device
       is  attached  to  (since linux supports more than one 1542 in the system at the same time)
       and (in this case) corresponds to the IO Port number (hex) of the controller (this is  the
       host adapter id number).  The "c0" represents the channel number (since some host adapters
       can drive multiple scsi busses).  The "i0l0" indicates that this device is scsi ID 0, with
       lun 0.  Finally the "p1" indicated partition number 1.


       -f     Flush everything from /dev/scsi prior to scanning the detected devices.  This means
              that new device nodes will be created even if the old ones were OK.

       -d     Sanitize by deletion. The .shadow. backup files will not be created, so  you  loose
              all non-default ownership/permissions that may have been set.

       -n     Don't  touch  device nodes for non-existing SCSI devices.  This might have security
              implications and is therefore not recommended.

       -l     Symbolic link mode.  Instead of creating nodes, symbolic links  are  created  which
              point  to  the  older  /dev/sda1 types of device nodes. When using this option, the
              permissions of the /dev/XXX device nodes will be changed to match the  ones  stored
              in /dev/scsi/YYY file, if present.

       -L     Use  symbolic  names  for the aliases assigned through the /etc/scsi.alias settings
              (see below).

       -m mode
              Specifies the mode (permissions) for new entries that need to be created.

       -c maxmiss
              Normally, if scsidev fails to open a generic scsi device, it finishes its scan  for
              devices.  With  this  option,  it goes on until maxmiss missing devices were found.
              This is only used, if you don't  have  the  /proc/scsi/scsi  extensions  for  large

       -A aliasfile
              Use an alternative file instead of the default /etc/scsi.alias (see below).

       -r     scsidev  does  first  probe  the  generic  and  then -- if appropriate -- the other
              highlevel devices (st, sd, sr). For removable devices (sd,  sr,  osst),  this  will
              fail, if no medium is inserted, so scsidev can not ensure, that the device actually
              corresponds to the one reported by the sg interface. After the first  device  scan,
              the situation is clear and scsidev will do the right guesses. So using -r in bootup
              scripts is safe. After you removed devices from your SCSI config, it isn't safe any
              longer.   This is only needed, if you don't have the /proc/scsi/scsi extensions for
              large disks.

       -M     Multipath support.  scsidev normally does complain if a line in scsi.alias  matches
              more than one device and does not create an alias then. With multipatch support on,
              it just creates the alias for the first device found matching  the  description  in
              the scsi.alias description.

       -e     Instructs  scsidev  to  use devfs like names, i.e. using the cbtu (controller, bus,
              target unit) characters instead of hcil (host, channel, scsi Id, scsi Lun) to build
              the device name.

       -o     Instructs  scsidev  to  use  scd  instead of sr for the old names of CD-ROM devices
              (relevant for symlink mode).

       -s     Tells scsidev
               to print out the device serial numbers of all detected devices on the system. This
              string can be useful for forming aliases.  If supported, also the WWID is printed.

       -v     Verbosity.   Mainly  used  for  debugging  purposes.   Use  multiple times for more

       -q     Be Quiet.  Only produce output, if there are errors.

       -h     Output short usage summary and copyright info and exit.


       It was intended that scsidev be useful without any configuration at all.  There are  times
       when  it  is  much  more  convenient  to  have  symbolic names for various devices.  These
       symbolic names should track devices as they get moved from controller to another, or  even
       if the SCSI id number is changed.

       The  general  idea  is  that there is a configuration file /etc/scsi.alias which lists the
       aliases that scsidev will attempt to create.  Each line represents a separate  alias,  and
       consists of a series of tokens.  Here are a couple of example entries:
       serial_number="DX908FK", devtype=disk, alias=fourgig
       manufacturer=WANGTEK, devtype=tape, alias=qictape
       id=2, devtype=generic, alias=cdwriter
       The  minimum  requirements are that each line have a alias and a devtype field.  The alias
       will be used to build the pathnames, and the devtype must be  one  of  disk,  tape,  osst,
       cdrom or generic.

       The  additional  qualifiers are optional, and you must specify a sufficient number of them
       such that the alias will match only one device.  The allowable qualifiers are:

              Specifies the name of the manufacturer.  This is the same string that is printed at
              boot time, and is also available through /proc/scsi.

       model= Specifies  the model number of the device.  This is the same string that is printed
              at boot time, and is also available through /proc/scsi.

       rev=   Specifies the revision string of the device.  This  is  the  same  string  that  is
              printed at boot time, and is also available through /proc/scsi.

              Specifies the serial number of the device.  Not all devices implement this, but for
              those that do it provides a convenient mechanism to uniquely identify a  device  no
              matter  where  it is found on the scsi chain. The serial number is the one reported
              in INQUIRY page 0x80 with EVPD=1. It is displayed by scsidev -s .

       wwid=  Specifies the WWID number of a device. This is a 64bit world  wide  unique  number,
              which  is  supported  by  SCSI-3  devices  and  reported via INQUIRY page 0x83 with
              EVPD=1. If supported, it's displayed by scsidev -s .

       id=    Specifies the scsi id number for the device.

       lun=   Specifies the lun for the device.  Most devices have a lun of 0,  and  it  is  only
              special devices such as cd changers that implement multiple lun devices.

       chan=  Specifies  which  channel  (i.e.  which  bus) for host adapters that drive multiple

              Specifies the partition number for disk drives.  If  unspecified,  the  alias  will
              match all partitions on the disk.

              Specifies the host adapter id number (0x334 part of sdh4-334c0i0l0p1 for example).

              Specifies  the unique number that each host adpater driver returns.  Generally this
              number is always 0 except for cases where the driver supports more than one  device
              of a given type on the system.

              Specifies the host adapter driver name. (Only the given chars need to match, so you
              may omit the version number.)

       Note that the specifiers which take string arguments can be quoted if the string  contains

       For  disks,  aliases  for all partitions will be created (unless partition= is specified).
       The names get a -pN suffix (N indicating the number of the partition. For  tapes  (st  and
       osst type), the non-rewinding variant with an n prepended will be created automatically.


        ... was written by Eric Youngdale <>
        ... was enhanced by Kurt Garloff <>


       Probably there are ...

       The  BIOS  and  LILO do not have the knowledge about the SCSI devices at boot time, so you
       still have to ensure, your kernel can be loaded when you insert a new disk.


       This program is free software. You can use it under the terms  of  the  GNU  GPL  (General
       Public  License) Version 2 (or any later version, at your option).  Note, that the GNU GPL
       implies, that there is NO WARRANTY at  all.   Full  text  of  the  GPL  can  be  found  in
       /usr/share/common-licenses/GPL file.


       scsidev is available from
       and will also be put on standard anonymous ftp servers.
       The old version is available from