SG_SANITIZE(8)							     SG3_UTILS							    SG_SANITIZE(8)

NAME

       sg_sanitize - remove all use data from a SCSI disk

SYNOPSIS

       sg_sanitize  [--block] [--count=OC] [--crypto] [--early] [--help] [--invert] [--ipl=LEN] [--overwrite] [--pattern=PF] [--quick] [--verbose]
       [--version] [--wait] DEVICE

DESCRIPTION

       This utility invokes the SCSI SANITIZE command. This command was first introduced in the SBC-3 revision 27 draft. The purpose of the  sani-
       tize operation is to alter the information in the cache and on the medium of a logical unit (e.g. a disk) so that the recovery of user data
       is not possible. If that user data cannot be erased, or is in the process of being erased, then the sanitize operation prevents	access	to
       that user data.

       Once  a	SCSI  SANITIZE	command  has successfully started, then user data from that disk is no longer available. Even if the disk is power
       cycled, the sanitize operation will continue after power is re-instated until it is complete.

       This utility requires either the --block, --crypto or --overwrite option. If the --quick option is not given then the user if given 15 sec-
       onds  to reconsider whether they wish to erase all the data on a disk. The disk's INQUIRY response strings are printed out just in case the
       wrong DEVICE has been given.

       If the --early option is given this utility will exit soon after starting the SANITIZE command with the IMMED bit set. The user can monitor
       the  progress  of  the sanitize operation with the "sg_request --num=9999 --progress" which sends a REQUEST SENSE command every 30 seconds.
       Otherwise if the --wait option is given then this utility will wait until the SANITIZE command completes (or fails) and that  can  be  many
       hours.

       If  neither  the  --early  nor  --wait option is given then the SANITIZE command is started with the IMMED bit set. After that this utility
       sends a REQUEST SENSE command every 60 seconds until there are no more progress indications.

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.

       -B, --block
	      perform a "block erase" sanitize operation.

       -c, --count=OC
	      where  OC  is  the "overwrite count" associated with the "overwrite" sanitize operation. OC can be a value between 1 and 31 and 1 is
	      the default.

       -C, --crypto
	      perform a "cryptographic erase" sanitize operation.

       -e, --early
	      the default action of this utility is to poll the disk every 60 seconds to fetch the progress indication until the sanitize is  fin-
	      ished. When this option is given this utility will exit "early" as soon as the sanitize has commenced. This option and --wait cannot
	      both be given.

       -h, --help
	      print out the usage information then exit.

       -i, --ipl=LEN
	      set the initialization pattern length to LEN bytes. By default it is set to the length of the pattern file (PF).	Only  active  when
	      the  --overwrite	option	is also given. It is the number of bytes from the PF file that will be used as the initialization pattern.
	      The minimum size is 1 byte and the maximum is the logical block size of the DEVICE (and not to exceed 65535). If LEN exceeds the	PF
	      file size then the initialization pattern is padded with zeros.

       -I, --invert
	      set the INVERT bit in the overwrite service action parameter list. This only affects the "overwrite" sanitize operation. The default
	      is a clear INVERT bit. When the INVERT bit is set then the initialization pattern is inverted between consecutive overwrite passes.

       -O, --overwrite
	      perform an "overwrite" sanitize operation. When this option is given then the --pattern=PF option is required.

       -p, --pattern=PF
	      where PF is the filename of a file containing the initialization pattern required by an "overwrite" sanitize operation.  The  length
	      of  this	file will be used as the length of the initialization pattern unless the --ipl=LEN option is given. The length of the ini-
	      tialization pattern must be from 1 to the logical block size of the DEVICE.

       -Q, --quick
	      the default action (i.e. when the option is not given) is to give the user 15 seconds to reconsider doing a  sanitize  operation	on
	      the DEVICE.  When this option is given that step (i.e. the 15 second warning period) is skipped.

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

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

       -w, --wait
	      the  default  action  (i.e. without this option and the --early option) is to start the SANITIZE command with the IMMED bit set then
	      poll for the progress indication with the REQUEST SENSE command until the sanitize operation  is	complete  (or  fails).	When  this
	      option  is  given  (and  the --early option is not given) then the SANITIZE command is started with the IMMED bit clear. For a large
	      disk this might take hours. [A cryptographic erase operation could potentially be very quick.]

NOTES

       The SCSI SANITIZE command is closely related to the ATA SANITIZE command, both are relatively new with the ATA command being the first  one
       defined.   It  is  likely  that	a  SCSI to ATA Translation (SAT) definition will soon appear for the SCSI SANITIZE command (most likely in
       SAT-3).

       The SCSI SANITIZE command is related to the SCSI FORMAT UNIT command. It is likely that a block erase sanitize operation would take a simi-
       lar  amount of time as a format on the same disk (e.g. 9 hours for a 2 Terabyte disk). The primary goal of a format is the configuration of
       the disk at the end of a format (e.g. different logical block size or protection information added). Removal of user data is  only  a  side
       effect  of  a  format.	With  the SCSI SANITIZE command, removal of user data is the primary goal.  If a sanitize operation is interrupted
       (e.g. the disk is power cycled) then after power up any remaining user data will not be available and the sanitize operation will continue.
       When  a	format	is interrupted (e.g. the disk is power cycled) the drafts say very little about the state of the disk. In practice some of
       the original user data may remain and the format may need to be restarted.

EXAMPLES

       These examples use Linux device names. For suitable device names in other supported Operating Systems see the sg3_utils(8) man page.

       As a precaution if this utility is called with no options then apart from printing a usage message, nothing happens:

	  sg_sanitize /dev/sdm

       To do a "block erase" sanitize the --block option is required.  The user will be given a 15 second period to reconsider, the SCSI  SANITIZE
       command	will  be  started with the IMMED bit set, then this utility will poll for a progress indication with a REQUEST SENSE command until
       the sanitize operation is finished:

	  sg_sanitize --block /dev/sdm

       To start a "block erase" sanitize and return from this utility once it is started (but not yet completed) use the --early option:

	  sg_sanitize --block --early /dev/sdm

       If the 15 second reconsideration time is not required add the --quick option:

	  sg_sanitize --block --quick --early /dev/sdm

       To do an "overwrite" sanitize a pattern file is required:

	  sg_sanitize --overwrite --pattern=rand.img /dev/sdm

       If the length of that "rand.img" is 512 bytes (a typically logical block size) then to use only the first  17  bytes  (repeatedly)  in  the
       "overwrite" sanitize operation:

	  sg_sanitize --overwrite --pattern=rand.img --ipl=17 /dev/sdm

EXIT STATUS

       The  exit status of sg_sanitize is 0 when it is successful. Otherwise see the sg3_utils(8) man page. Unless the --wait option is given, the
       exit status may not reflect the success of otherwise of the format.

AUTHORS

       Written by Douglas Gilbert.

REPORTING BUGS

       Report bugs to <dgilbert at interlog dot com>.

COPYRIGHT

       Copyright (C) 2011 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_requests(8), sg_format(8)

sg3_utils-1.32							     June 2011							    SG_SANITIZE(8)