fsck_ufs - file system  consistency  check  and  interactive


     fsck -F ufs [generic-options] [special...]

     fsck -F ufs  [generic-options]  [-o specific-options]  [spe-


     The fsck utility audits  and  interactively  repairs  incon-
     sistent  conditions  on  file  systems.  A file system to be
     checked may be specified by giving the name of the block  or
     character  special device or by giving the name of its mount
     point if a matching entry exists in /etc/vfstab.

     The special parameter represents the character special  dev-
     ice, for example, /dev/rdsk/c1t0d0s7, on which the file sys-
     tem resides. The character special  device,  not  the  block
     special  device  should  be used.  The fsck utility will not
     work on a block device  if  the  block  device  is  mounted,
     unless the file system is error-locked.

     If no special device is  specified,  all  ufs  file  systems
     specified  in  the   vfstab  with  a  fsckdev  entry will be
     checked. If the -p (``preen'') option is specified, ufs file
     systems  with an fsckpass number greater than  1 are checked
     in parallel. See fsck(1M).

     In  the  case  of  correcting  serious  inconsistencies,  by
     default,   fsck asks for confirmation before making a repair
     and waits for the operator to respond either yes or no.   If
     the operator does not have write permission on the file sys-
     tem,  fsck will default to a  -n  (no  corrections)  action.
     See  fsck(1M).

     Repairing some file system  inconsistencies  can  result  in
     loss of data.
      The amount and severity of data loss can be determined from
     the diagnostic output.

     The fsck utility  automatically  corrects  innocuous  incon-
     sistencies  such  as  unreferenced  inodes,  too-large  link
     counts in inodes, missing blocks in the  free  list,  blocks
     appearing  in  the free list and also in files, or incorrect
     counts in the super block. It displays a  message  for  each
     inconsistency  corrected  that  identifies the nature of the
     correction on the file system which took place.  After  suc-
     cessfully  correcting  a file system, fsck prints the number
     of files on that file system, the number of  used  and  free
     blocks, and the percentage of fragmentation.
     Inconsistencies checked are as follows:

        o  Blocks claimed by more than  one  inode  or  the  free

        o  Blocks claimed by an inode or the  free  list  outside
           the range of the file system.

        o  Incorrect link counts.

        o  Incorrect directory sizes.

        o  Bad inode format.

        o  Blocks not accounted for anywhere.

        o  Directory checks, file pointing to unallocated  inode,
           inode  number  out  of  range, and absence of  `.' and
           `..' as the first two entries in each directory.

        o  Super Block checks: more blocks for inodes than  there
           are in the file system.

        o  Bad free block list format.

        o  Total free block and/or free inode count incorrect.

     Orphaned files and directories (allocated but  unreferenced)
     are, with the operator's concurrence, reconnected by placing
     them in the  lost+found directory. The name assigned is  the
     inode  number.   If the lost+found directory does not exist,
     it is created.   If  there  is  insufficient  space  in  the
     lost+found directory, its size is increased.

     An attempt to mount a ufs file system with the  -o  nolarge-
     files option will fail if the file system has ever contained
     a large file (a file whose size is greater than or equal  to
     2  Gbyte).  Invoking fsck resets the file system state if no
     large files are present in the  file  system.  A  successful
     mount  of  the file system after invoking fsck indicates the
     absence of large files in the file system.  An  unsuccessful
     mount  attempt  indicates the presence of at least one large
     file. See mount_ufs(1M).


     The generic-options consist of the following options:

     -m    Check but do not repair. This option checks  that  the
           file  system  is  suitable for mounting, returning the
           appropriate exit status. If the file system  is  ready
           for mounting, fsck displays a message such as:

                 ufs fsck: sanity check: /dev/rdsk/c0t3d0s1 okay

     -n|N  Assume a no response to all questions asked  by  fsck;
           do not open the file system for writing.

     -V    Echo the expanded command line, but do not execute the
           command.  This  option  may  be  used to verify and to
           validate the command line.

     -y|Y  Assume a yes response to all questions asked by fsck.

     See generic  fsck(1M) for the details  for  specifying  spe-

     -o specific-options
           Specify  ufs  file  system  specific  options.   These
           options  can  be  any  combination  of  the  following
           separated by commas (with no intervening spaces).

           b=n   Use block  n as the super  block  for  the  file
                 system.  Block 32 is always one of the alternate
                 super blocks.
                  Determine the  location of other  super  blocks
                 by running newfs(1M) with the -Nv options speci-

           c     If the file system is in the old (static  table)
                 format,  convert  it  to the new (dynamic table)
                 format. If the file system is in the new format,
                 convert  it  to  the old format provided the old
                 format can support the  file  system  configura-
                 tion.   In  interactive mode, fsck will list the
                 direction the conversion is to be made  and  ask
                 whether  the  conversion  should  be  done. If a
                 negative answer is given, no further  operations
                 are  done on the file system. In preen mode, the
                 direction of the conversion is listed  and  done
                 if possible without user interaction. Conversion
                 in preen mode is best used  when  all  the  file
                 systems  are being converted at once. The format
                 of a file system  can  be  determined  from  the
                 first  line of output from fstyp(1M).  Note: the
                 c option is seldom used and is included only for
                 compatibility  with  pre-4.1 releases.  There is
                 no guarantee that this option will  be  included
                 in future releases.

           f     Force checking of file systems regardless of the
                 state of their super block clean flag.

           p     Check and fix the file system  non-interactively
                 ("preen").  Exit immediately if there is a prob-
                 lem  requiring  intervention.  This  option   is
                 required  to  enable parallel file system check-

           w     Check writable file systems only.


           list of default parameters for each file system


     See attributes(5) for descriptions of the  following  attri-

    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    | Availability                | SUNWcsu                     |


     clri(1M), fsck(1M),  fsdb_ufs(1M),  fsirand(1M),  fstyp(1M),
     mkfs(1M),    mkfs_ufs(1M),    mount_ufs(1M),   mountall(1M),
     newfs(1M),  reboot(1M),  vfstab(4),  attributes(5),   large-
     file(5), ufs(7FS),


     The operating system buffers file system data.  Running fsck
     on  a  mounted  file system can cause the operating system's
     buffers to become out of date with respect to the disk.  For
     this  reason,  the file system should be unmounted when fsck
     is used. If this is not possible, care should be taken  that
     the  system is quiescent and that it is rebooted immediately
     after fsck is run. Quite often, however, this  will  not  be
     sufficient.   A panic will probably occur if running fsck on
     a file system modifies the file system.


     It is usually faster to check the character  special  device
     than the block special device.

     Running fsck on file systems larger than 2 Gb fails  if  the
     user chooses to use the  block interface to the device:

     fsck /dev/dsk/c?t?d?s?

     rather than the raw (character special) device:

     fsck /dev/rdsk/c?t?d?s?

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