NAME

       sg_reassign - send SCSI REASSIGN BLOCKS command

SYNOPSIS

       sg_reassign  [--address=A,A...]  [--dummy]  [--eight=0|1] [--grown] [--help] [--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 suspected 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.

       -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  invocation  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  addresses  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 associated 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 reassigned blocks and the grown defect list.
              This list is sometimes referred to as the GLIST.

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

       -l, --longlist=0 | 1
              sets the REASSIGN BLOCKS cdb field of the same name to the given value.  Only 1000  addresses  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 automatic 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 number 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 access).

       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 reassigned 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 © 2005-2014 Douglas Gilbert
       This  software is distributed under a FreeBSD license. There is NO warranty; not even for MERCHANTABILITY
       or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

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