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Alphabetical listing for F

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fsck(8)
NAME
  fsck, ufs_fsck - Check and repair UFS file systems

SYNOPSIS
  /usr/sbin/fsck [fs_options] [filesystem...]

OPTIONS
  The following options are interpreted by fsck:

  -b block
      Uses the specified block number as the super block for the file system.
      Block 32 is usually an alternate super block.

  -B  Converts UFS Version 4 back to UFS Version 3. When you use the -B
      option on a UFS Version 4 file system, it will be marked as a Version 3
      file system if there are no files or directories with more than 32767
      hardlinks or 32765 subdirectories.

  -c  If the file system is in the old (static table) format, this option
      converts it to the new (dynamic table) format. If the file system is in
      the new format, this option converts it to the old format, provided
      that the old format can support the file system configuration.  In
      interactive mode, fsck lists the direction of the conversion and asks
      if the conversion should be done. If you answer "no," no further
      operations are done on the file system. If the -p option is specified,
      the direction of the conversion is listed and the conversion is
      performed without user interaction if possible. The -p option should be
      used if all the file systems are being converted simultaneously. The
      format of a file system can be determined from the first line of output
      from the dumpfs command.

  -f  Forces fsck to check the root file system, even when the file system is
      mounted as writable. Use this option with caution, because running fsck
      on a mounted root file system can cause its files to become out of
      synchronization with running system data.	 If the problem occurs, the
      fsck program displays a message recommending you reboot the system.

  -l number
      Limits the number of parallel checks to the number specified.  By
      default, the limit is the number of disks running one process per disk.
      If a smaller limit is given, the disks are checked using a round
      robin-type schedule, one file system at a time.

  -m mode
      Uses the mode specified in octal as the permission bits to use when
      creating the lost+found directory rather than the default 777. In
      particular, systems that do not want to have lost files accessible by
      all users on the system should use a more restrictive set of
      permissions, such as 700.

  -n  Answers "no" to all the prompts except for the "CONTINUE?" prompt. The
      option does not write to the lost+found file in the file system.	If
      you do not have write permission on the file system, fsck defaults to
      the behavior of the -n option.

  -o  Causes fsck to unconditionally check the file system even if the file
      system's clean byte is set.  That is, a file system is checked even if
      it has been unmounted cleanly.

  -p  Noninteractively corrects the following file system inconsistencies:
      unreferenced inodes, link counts in inodes that are too large, missing
      blocks in the free map, blocks in the free map that are also in files,
      and wrong counts in the super-block.

  -v  Causes more extensive messages to be displayed during the file system
      checks (verbose mode).

  -y  Answers "yes" to all the prompts. This option should be used with
      caution because the integrity of the file system data can be corrupted
      by answering "yes" to all the prompts.

DESCRIPTION
  The fsck command is a front-end program for the ufs_fsck program, which
  checks and repairs UFS file systems. Do not use this command for AdvFS file
  systems:  instead, see advfs(4).

  The fsck program has more consistency checks than its check, dcheck,
  fcheck, and icheck predecessors combined.

  You must be root to use this command.

  If you do not specify a file system in the command line, the fsck command
  checks the file systems in the /etc/fstab file.

  With one exception, the fsck command cannot be used on an active file
  system. The command checks to determine whether the partition to be
  checked, or an overlapping partition, is in use.  The exceptional case
  occurs when you run the command on an active root file system and specify
  the -f option. Use this option with caution, because it can cause the data
  on the running system (the in-memory data) to become unsynchronized from
  the file system data (the on-disk data).

  The fsck program interactively repairs inconsistent file system conditions.
  If the file system is found to be consistent, the number of files, blocks
  used, and free blocks are reported.  If the file system is inconsistent,
  you are prompted before each correction is attempted. For each corrected
  inconsistency, one or more lines are displayed, identifying the file system
  on which the correction takes place and the type of correction.  After
  successfully correcting a file system, the fsck program displays the number
  of files on that file system, the number of used and free blocks, and the
  percentage of fragmentation.

  The default behavior of the fsck program is to interactively check the
  following UFS file system inconsistencies:

       Blocks claimed by more than one inode or the free map
       Blocks claimed by an inode outside the range of the file system
       Incorrect link counts
       Size checks: directory size not of proper format; partially truncated file
       Bad inode format
       Blocks not accounted for anywhere
       Directory checks: file pointing to unallocated inode; inode number out of range; . (dot) or .. (dot dot) not the first two entries of a directory or having the wrong inode number
       Super Block checks: more blocks for inodes than there are in the file system
       Bad free block map format
       Total free block and/or free inode count incorrect

  If you use the -p option, the fsck program noninteractively attempts to
  correct specific file system inconsistencies.	 The corrections are made
  only if they can be done safely. The fsck program can noninteractively
  correct the following file system inconsistencies:

       Unreferenced inodes
       Link counts in inodes that are too large
       Missing blocks in the free map
       Blocks in the free map that are also in files
       Wrong counts in the super-block.

  If fsck encounters any other inconsistencies, it exits with an abnormal
  return status and a subsequent reboot will fail.

  The system makes sure that only a restricted class of innocuous
  inconsistencies can occur unless hardware or software failures intervene.

  Note that some of the corrective actions can result in a loss of data.  The
  amount and severity of data lost can be determined from the diagnostic
  output.

  At system boot, fsck -p runs automatically and reads the /etc/fstab file to
  determine which file systems to check. Only partitions that are mounted rw
  or ro and have a non-zero pass (1 or more) number are checked.  File
  systems that have a pass number 1 (usually only the root file system) are
  checked one at a time.  When pass 1 completes, the remaining pass numbers
  are processed with one parallel fsck process running per disk drive in the
  same pass.

  The per disk drive logic is based on the /dev/disk/dsk0a syntax where
  different partition letters are treated as being on the same disk drive.
  Partitions layered on top of an LSM device may not follow this naming
  convention.  Where LSM is used, you can use unique pass numbers in the
  /etc/fstab file to sequence the fsck checks.

  If a QUIT signal is sent, fsck finishes the file system checks and then
  exits with an abnormal return status that causes the automatic reboot to
  fail. This is useful if you want to finish the file system checks during an
  automatic reboot but do not want the machine to come up multiuser after the
  checks complete.

  If the fsck default program fails (terminates with a non-zero value), fsck
  terminates with the exit value.  This ensures that the auto-reboot
  dependencies, such as those commonly used in the run command script,
  continue to function.

  If orphaned files or directories (allocated but unreferenced) are found,
  you are asked if you want to reconnect the files and directories that are
  not empty by putting them in the lost+found directory.  The program
  indicates whether the file or directory is empty or not empty.  The fsck
  program reconnects directories that are not empty and assigns the inode
  number for the name.	If the lost+found directory does not exist, it is
  created, and if it has insufficient space, the size is increased. Empty
  files and directories are removed unless you specify the -n option.

ERRORS
  The following message indicates that the system is avoiding a potential
  panic by skipping the file system check:

       /dev/disk/dsk2g: skipping filesystem already mounted (read-write) on '/usr'

  The following message indicates that the file system is mounted:

       /dev/disk/dsk2g on /usr: Device busy

  The following message indicates that the partition you are checking is
  open:

       ERROR: /dev/rdisk/dsk3a or an overlapping partition is open
       fsck cannot be run on an active filesystem

EXAMPLES
  The following is an example of an /etc/fstab file that is used in the
  examples in this section:

       /dev/disk/dsk2a	   /	       ufs rw 1 1
       /dev/disk/dsk0g	   /usr	       ufs rw 1 2
       /dev/disk/dsk2b	   swap1       ufs sw 0 2
       /dev/disk/dsk0b	   /public     ufs sw 0 2
       /dev/disk/dsk2g	   /var	       ufs rw 1 2
       /dev/disk/dsk3c	   /usr/users  ufs rw 1 2

  The following command checks all the file systems in the /etc/fstab file
  but makes no corrections:

       # fsck -n

  The following example checks a file system found in the /etc/fstab file and
  checks a file system that is not found in the /etc/fstab file:

       # fsck  /dev/rdisk/dsk3c	 /dev/rdisk/dsk1a

  The following command noninteractively checks the file systems in the
  /etc/fstab file:

       # fsck -p

FILES
  /usr/sbin/fsck
      Specifies the command path.

  /usr/sbin/ufs_fsck
      Specifies the command path.

  /etc/fstab
      Contains the default list of file systems to check.

SEE ALSO
  Commands: newfs(8)

Index for Section 8

Alphabetical listing for F

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