Provided by: sg3-utils_1.46-1build1_amd64 bug


       sg_sanitize - remove all user data from disk with SCSI SANITIZE command


       sg_sanitize  [--ause]  [--block]  [--count=OC]  [--crypto]  [--dry-run] [--desc] [--early]
       [--fail]  [--help]   [--invert]   [--ipl=LEN]   [--overwrite]   [--pattern=PF]   [--quick]
       [--test=TE] [--timeout=SECS] [--verbose] [--version] [--wait] [--zero] [--znr] DEVICE


       This  utility  invokes the SCSI SANITIZE command. This command was first introduced in the
       SBC-3 revision 27 draft. The purpose of the sanitize 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, --fail or --overwrite option. With the
       --block, --crypto or --overwrite option the user is given 15 seconds to reconsider whether
       they  wish  to  erase  all the data on a disk, unless the --quick option is given in which
       case the sanitize operation starts immediately. The disk's INQUIRY  response  strings  are
       printed out just in case the wrong DEVICE has been given.

       If  the  --early  option  is  given  then  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_requests --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  the --wait option is not given then the SANITIZE command is started with the IMMED bit
       set. If neither the --early nor the --wait options are given then  this  utility  sends  a
       REQUEST  SENSE command after every 60 seconds until there are no more progress indications
       in which case this utility exits silently. If additionally the --verbose option  is  given
       the exit will be marked by a short message that the sanitize seems to have succeeded.


       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, --ause
              sets the AUSE bit in the cdb. AUSE is an acronym for "allow  unrestricted  sanitize
              exit". The default action is to leave the AUSE bit cleared.

       -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. Note that this erase  is  often
              very  quick as it simply overwrites an internal cryptographic key with a new value.
              Those keys are not accessible to users and encrypt all data  written  then  decrypt
              all  data  read  from  the media. The primary reason for doing that is to make this
              operation fast. This operation can not be reversed.

       -d, --desc
              sets the DESC field in the REQUEST SENSE command used for polling. By default  this
              field  is  set  to  zero.  A  REQUEST SENSE polling loop is used after the SANITIZE
              command is issued (assuming that neither the --early nor  the  --wait  option  have
              been given) to check on the progress of this command as it can take some time.

       -D, --dry-run
              this  option  will  parse  the  command line, do all the preparation but bypass the
              actual SANITIZE command.

       -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 finished. When this option is given
              this utility will exit "early" as soon as the SANITIZE command with the  IMMED  bit
              set to 1 has been acknowledged. This option and --wait cannot both be given.

       -F, --fail
              perform an "exit failure mode" sanitize operation. Typically requires the preceding
              SANITIZE command to have set the AUSE bit.

       -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) or 4 if the --zero option is given. 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 (if the --zero option is not
              given).  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 or the --zero 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  initialization 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.

       -T, --test=TE
              set the TEST field in the  overwrite  service  action  parameter  list.  This  only
              affects  the  "overwrite"  sanitize  operation.  The  default is to place 0 in that

       -t, --timeout=SECS
              where SECS is the number of seconds used for the timeout on the SANITIZE command.

       -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.]

       -z, --zero
              with  an  "overwrite"  sanitize  operation  this  option  causes the initialization
              pattern to be zero (4 zeros are used as the initialization pattern). Cannot be used
              with  the --pattern=PF option. If this option is given twice (e.g. '-zz') then 0xff
              is used as the initialization byte.

       -Z, --znr
              sets ZNR bit (zoned no reset) in cdb. Introduced in the SBC-4 revision 7 draft.


       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.  The SCSI to ATA
       Translation (SAT) definition for the SCSI SANITIZE command appeared in the SAT-3  revision
       4 draft.

       When  a  SAT  layer is used to a (S)ATA disk then for OVERWRITE the initialization pattern
       must be 4 bytes long. So this means either the --zero option may be given,  or  a  pattern
       file  (with  the  --pattern=PF option) that is 4 bytes long or set to that length with the
       --ipl=LEN option.

       The SCSI SANITIZE command is related to the SCSI FORMAT UNIT command. It is likely that  a
       block erase sanitize operation would take a similar 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.

       Finding out whether a disk (SCSI or ATA) supports SANITIZE can be a challenge. If the user
       really  needs  to  find  out  and  no other information is available then try 'sg_sanitize
       --fail -vvv <device>' and observe the sense data returned  may  be  the  safest  approach.
       Using  the  --fail  variant  of  this  utility  should have no effect unless it follows an
       already failed sanitize operation. If the SCSI REPORT SUPPORTED  OPERATION  CODES  command
       (see  sg_opcodes)  is  supported  then  using it would be a better approach for finding if
       sanitize is supported.

       If using the dd command to check the before and after data of  a  particular  block  (i.e.
       check  the  erase  actually  worked)  it is a good idea to use the 'iflag=direct' operand.
       Otherwise the first read might be cached and returned when the same LBA is read  a  little
       later. Obviously this utility should only be used to sanitize data on a disk whose mounted
       file systems (if any) have been unmounted prior to the erase!


       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 may be given:

          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

       To overwrite with zeros use:
          sg_sanitize --overwrite --zero /dev/sdm


       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.

       The  Unix  convention is that "no news is good news" but that can be a bit unnerving after
       an operation like sanitize, especially if it  finishes  quickly  (i.e.  before  the  first
       progress  poll  is sent). Giving the --verbose option once should supply enough additional
       output to settle those nerves.


       Written by Douglas Gilbert.


       Report bugs to <dgilbert at interlog dot com>.


       Copyright © 2011-2020 Douglas Gilbert
       This software is distributed under a FreeBSD license. There is NO warranty; not  even  for


       sg_requests(8), sg_format(8)