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] [--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 con-
	      tains "#" 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.

       -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 per-
	      mitted. See the discussion below concerning the relationship between reassigned blocks and the grown defect list. This list is some-
	      times 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 recov-
       erable 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 (C) 2005-2012 Douglas Gilbert
       This software is distributed under a FreeBSD license. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A  PARTICULAR  PUR-
       POSE.

SEE ALSO

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

sg3_utils-1.35							   November 2012						    SG_REASSIGN(8)