phpman > man > sg_reassign(8)

SG_REASSIGN(8)                                SG3_UTILS                               SG_REASSIGN(8)



NAME
       sg_reassign - send SCSI REASSIGN BLOCKS command

SYNOPSIS
       sg_reassign   [--address=A,A...]   [--dummy]   [--eight=0|1]   [--grown]   [--help]   [--hex]
       [--longlist=0|1] [--primary] [--verbose] [--version] DEVICE

DESCRIPTION
       Send a SCSI REASSIGN BLOCKS command to DEVICE. Alternatively this utility can find the number
       of  element  in a "grown" or "primary" defect list with a SCSI READ DEFECT DATA (10) command.
       These SCSI commands are defined in SBC-2 for direct access devices (e.g.  a  disk).  Reassign
       blocks  is  designed to change the physical location of a logical block that is known or sus‐
       pected to be defective to another area on the  media.  Disks  are  typically  formatted  with
       blocks held in reserve for this situation.

       If neither the --grown nor --primary option is supplied then one or more addresses need to be
       given. If the address (or all of the addresses) fit into 4 bytes and '--eight=1' is not given
       then  the  parameter  block passed to DEVICE is made up of 4 byte logical block addresses. If
       any of the addresses need more than 4 bytes to represent (i.e. >= 2**32)  or  '--eight=1'  is
       given then the parameter block passed to DEVICE is made up of 8 byte logical block addresses.

OPTIONS
       Arguments  to long options are mandatory for short options as well.  The options are arranged
       in alphabetical order based on the long option name.

       -a, --address=A,A...
              where A,A... is a string of comma separated numbers. Each  number  is  interpreted  as
              decimal unless prefixed by '0x' or '0X' (or it has a trailing 'h' or 'H'). If multiple
              logical block addresses are given they must be separated by  a  comma  or  a  (single)
              space.  A  string  that contains any space separators needs to be quoted. At least one
              address must be given.

       -a, --address=-
              reads one or more logical block addresses from stdin. These may be comma,  space,  tab
              or  linefeed (newline) separated. If a line contains "#" then the remaining characters
              on that line are ignored. Otherwise each non separator sequence of  characters  should
              resolve  to  a decimal number unless prefixed by '0x' or '0X' (or has a trailing 'h').
              At least one address must be given. Lines should not be longer than 1023 bytes.

       -d, --dummy
              prepare for but do not execute the SCSI REASSIGN BLOCKS command.  Since  the  REASSIGN
              BLOCKS command is essentially irreversible, paranoid users may wish to check the invo‐
              cation of this utility before reassigning defective blocks  on  a  disk.  Useful  with
              '-vv' for those who wish to view the parameter block that will accompany the command.

       -e, --eight=0 | 1
              when value is 1 then it sets the 'LONGLBA' flag in the command indicating that the ad‐
              dresses in the associated parameter block are 8 byte quantities.  When value is 0 then
              it clears the 'LONGLBA' flag in the command indicating that the addresses in the asso‐
              ciated parameter block are 4 byte quantities.  If this option is not given then 4 byte
              quantities are assumed unless one of the address is too large.

       -g, --grown
              use  the SCSI READ DEFECT DATA (10) command to determine the number of elements in the
              "grown defect list". When this option is given there  is  no  reassignment  of  blocks
              (i.e.  this  utility is passive). When this option is given then the --address= option
              is not permitted. See the discussion below concerning the relationship  between  reas‐
              signed  blocks  and  the  grown defect list. This list is sometimes referred to as the
              GLIST.

       -h, --help
              output the usage message then exit.

       -H, --hex
              print response in hex (for -g, --grown, -p or --primary).

       -l, --longlist=0 | 1
              sets the REASSIGN BLOCKS cdb field of the same name to the given value.  Only 1000 ad‐
              dresses  are  permitted  so there should be no need to specify a value of 1. The short
              list variant restricts the parameter block length to 2 ** 16 bytes (i.e. about 16000 4
              byte addresses or 8000 8 byte addresses). Added for completeness.

       -p, --primary
              use  the SCSI READ DEFECT DATA (10) command to determine the number of elements in the
              "primary defect list" which is established during the manufacturing process. When this
              option  is  given  there  is no reassignment of blocks (i.e. this utility is passive).
              When this option is given then the --address= option is not permitted.  This  list  is
              sometimes referred to as the PLIST.

       -v, --verbose
              increase the level of verbosity, (i.e. debug output).

       -V, --version
              print the version string and then exit.

NOTES
       Note  that  if  the  ARRE field (for reads) and/or the AWRE field (for writes) are set in the
       "Read Write Error Recovery" mode page then recoverable read and/or write errors  cause  auto‐
       matic reassignment of the defective block. The PER bit in the same mode page controls whether
       a RECOVERED ERROR sense key is reported on not (PER=1 implies do report). Irrespective of the
       ARRE,  AWRE  or PER field settings, the error counter log pages reflect any errors (recovered
       or otherwise). Whenever a block is reassigned, a new entry is added  in  the  "grown"  defect
       list. Apart from doing selftests (see sg_senddiag or smartmontools) regularly, monitoring the
       grown defect list of a disk is a reasonable metric of its health. If the  grown  list  starts
       growing quickly that is an ominous sign. The best grown defect lists are empty ones. The num‐
       ber of elements in the grown defect list can be viewed with the --grown option. The  contents
       of the grown defect list can be viewed with the 'sginfo -G' utility.

       If  an  unrecoverable  error  is  detected at a logical block address then REASSIGN BLOCKS is
       needed to reassign the block. Also if the ARRE and/or AWRE fields are clear and a recoverable
       error  is  detected  then  the  logical block in question may be reassigned with this utility
       (otherwise the error counter log pages will continually be incremented for each recovered ac‐
       cess).

       The  number  of blocks held in reserve for the purposes of REASSIGN BLOCKS is vendor specific
       and may well be limited to the zone within the media where  the  original  (defective)  block
       lay.  When  this  number  is exhausted subsequent invocations of this utility may result in a
       sense key of hardware error and an additional sense of 'No defect spare location  available'.
       The next step would be to reformat the disk (or get a replacement).

       The  SBC-2  draft  standard (revision 16) notes that when multiple addresses are given to the
       SCSI REASSIGN BLOCKS command and there is some failure at one of the later addresses then all
       addresses  prior  to  that  have  already be reassigned. Care should be taken in such a case.
       Re-executing the command with the same addresses will cause the earlier addresses to be reas‐
       signed  again.  At some stage the disk will run out of reserved locations.  So unless a large
       number of addresses are involved it may be safer to reassign them one address at a time.

EXIT STATUS
       The exit status of sg_reassign is 0 when it is successful. Otherwise see the sg3_utils(8) man
       page.

AUTHORS
       Written by Douglas Gilbert.

REPORTING BUGS
       Report bugs to <dgilbert at interlog dot com>.

COPYRIGHT
       Copyright © 2005-2019 Douglas Gilbert
       This software is distributed under a FreeBSD license. There is NO warranty; not even for MER‐
       CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO
       sg_format,sginfo,sg_senddiag(all  in  sg3_utils),   sdparm(sdparm),   smartmontools(internet,
       sourceforge)



sg3_utils-1.45                              October 2019                              SG_REASSIGN(8)