badblocks

 

---

 BADBLOCKS(8)                                         BADBLOCKS(8)
 
 
 
NAME
        badblocks - search a device for bad blocks
 
SYNOPSIS
        badblocks [ -svwnf ] [ -b block-size ] [ -c blocks_at_once
        ] [ -i input_file ] [ -o output_file ] [ -p  num_passes  ]
        device [ last-block ] [ start-block ]
 
DESCRIPTION
        badblocks  is  used  to  search for bad blocks on a device
        (usually a disk partition).  device is  the  special  file
        corresponding  to  the device (e.g /dev/hdc1).  last-block
        is the last block to be checked; if it is  not  specified,
        the last block on the device is used as a default.  start-
        block is an optional  parameter  specifying  the  starting
        block  number  for  the  test, which allows the testing to
        start in the middle of the disk.  If it is  not  specified
        the first block on the disk is used as a default.
 
OPTIONS
        -b block-size
               Specify the size of blocks in bytes.
 
        -c number of blocks
               is the number of blocks which are tested at a time.
               The default is 16.   Increasing  this  number  will
               increase  the efficiency of badblocks but also will
               increase its memory usage.  Badblocks needs  memory
               proportional  to  the  number  of  blocks tested at
               once, in read-only mode, proportional to twice that
               number  in  read-write  mode,  and  proportional to
               three times that number  in  non-destructive  read-
               write mode.  If you set the number-of-blocks param­
               eter to too  high  a  value,  badblocks  will  exit
               almost  immediately  with  an  out-of-memory  error
               "while allocating buffers".  If you set it too low,
               however,  for  a  non-destructive-write-mode  test,
               then it's possble for  questionable  blocks  on  an
               unreliable  hard  drive to be hidden by the effects
               of the hard disk track buffer.
 
        -f     Normally, badblocks will refuse to do a  read/write
               or  a  non-destructive  test  on  a device which is
               mounted, since this can cause the system to  poten­
               tially  crash.   This  can be overriden using the -
               flag, but this should not be done under normal cir­
               cumstances.   The  only time when this option might
               be safe is if the /etc/mtab file is incorrect,  and
               the device really isn't mounted.
 
        -i input_file
               Read  a  list of already existing known bad blocks.
               Badblocks will skip testing these blocks since they
               are known to be bad.  If input_file is specified as
               "-", the list will be read from the standard input.
               Blocks listed in this list will be omitted from the
               list of new bad blocks  produced  on  the  standard
               output  or  in  the  output file.  The -b option of
               dumpe2fs(8) can be used to  retrieve  the  list  of
               blocks currently marked bad on an existing filesys­
               tem, in a format suitable for use with this option.
 
        -o output_file
               Write the list of bad blocks to the specified file.
               Without this option, badblocks displays the list on
               its  standard  output.   The format of this file is
               suitable for use by the -l option in  e2fsck(8)  or
               mke2fs(8).
 
        -p num_passes
               Repeat  scanning  the  disk  until there are no new
               blocks discovered in num_passes  consecutive  scans
               of  the disk.  Default is 0, meaning badblocks will
               exit after the first pass.
 
        -n     Use non-destructive read-write  mode.   By  default
               only  a  non-destructive  read-only  test  is done.
               This option  must  not  be  combined  with  the  -w
               option, as they are mutually exclusive.
 
        -s     Show  the  progress  of the scan by writing out the
               block numbers as they are checked.
 
        -v     Verbose mode.
 
        -w     Use write-mode test. With  this  option,  badblocks
               scans  for  bad  blocks  by  writing  some patterns
               (0xaa, 0x55, 0xff, 0x00)  on  every  block  of  the
               device,  reading every block and comparing the con­
               tents.  This option may not be compiled with the -n
               option, as they are mutually exclusive.
 
 WARNING
        Never  use the -w option on an device containing an exist­
        ing file system.  This option erases data!  If you want to
        do  write-mode testing on an existing file system, use the
        -n option instead.  It is slower,  but  it  will  preserve
        your data.
 
AUTHOR
        badblocks  was written by Remy Card <Remy.Card@linux.org>.
        Current maintainer is Theodore Ts'o  <tytso@alum.mit.edu>.
        Non-destructive read/write test implemented by David Beat­
        tie <dbeattie@softhome.net>.
 
 AVAILABILITY
        badblocks is part of the e2fsprogs package and  is  avail­
        able from http://e2fsprogs.sourceforge.net.
 
SEE ALSO
        e2fsck(8), mke2fs(8)
 
 
 
 E2fsprogs version 1.23     August 2001               BADBLOCKS(8)

---