1fsck_ufs(1M)            System Administration Commands            fsck_ufs(1M)
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NAME

6       fsck_ufs - file system consistency check and interactive repair
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SYNOPSIS

9       fsck -F ufs [generic-options] [special]...
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12       fsck -F ufs [generic-options] [-o specific-options]
13            [special]...
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DESCRIPTION

17       The  fsck  utility audits and interactively repairs inconsistent condi‐
18       tions on file systems. A file system to be checked may be specified  by
19       giving  the  name of the block or character special device or by giving
20       the name of its mount point if a matching entry exists in /etc/vfstab.
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23       The special parameter represents  the  character  special  device,  for
24       example,  /dev/rdsk/c1t0d0s7,  on  which  the  file system resides. The
25       character special device, not the block special device should be  used.
26       The  fsck  utility will not work if the block device is mounted, unless
27       the file system is error-locked.
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30       If no special device is specified, all ufs file  systems  specified  in
31       the  vfstab with a fsckdev entry will be checked. If the -p (``preen'')
32       option is specified, ufs file systems with an fsckpass  number  greater
33       than 1 are checked in parallel. See fsck(1M).
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36       In  the  case  of  correcting serious inconsistencies, by default, fsck
37       asks for confirmation before making a repair and waits for the operator
38       to  respond  either yes or no. If the operator does not have write per‐
39       mission on the file system, fsck will default to a -n (no  corrections)
40       action. See fsck(1M).
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43       Repairing  some file system inconsistencies can result in loss of data.
44       The amount and severity of data loss can be determined from  the  diag‐
45       nostic output.
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48       The  fsck utility automatically corrects innocuous inconsistencies such
49       as unreferenced inodes, too-large link counts in inodes, missing blocks
50       in  the free list, blocks appearing in the free list and also in files,
51       or incorrect counts in the super block. It displays a message for  each
52       inconsistency corrected that identifies the nature of the correction on
53       the file system which took place. After successfully correcting a  file
54       system, fsck prints the number of files on that file system, the number
55       of used and free blocks, and the percentage of fragmentation.
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58       Inconsistencies checked include:
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60           o      Blocks claimed by more than one inode or the free list.
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62           o      Blocks claimed by an inode or  the  free  list  outside  the
63                  range of the file system.
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65           o      Incorrect link counts.
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67           o      Incorrect directory sizes.
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69           o      Bad inode format.
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71           o      Blocks not accounted for anywhere.
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73           o      Directory  checks, file pointing to unallocated inode, inode
74                  number out of range, and absence of  `.'  and  `..'  as  the
75                  first two entries in each directory.
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77           o      Super Block checks: more blocks for inodes than there are in
78                  the file system.
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80           o      Bad free block list format.
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82           o      Total free block and/or free inode count incorrect.
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85       Orphaned files and directories (allocated but unreferenced)  are,  with
86       the   operator's  concurrence,  reconnected  by  placing  them  in  the
87       lost+found directory. The name assigned is the  inode  number.  If  the
88       lost+found  directory does not exist, it is created. If there is insuf‐
89       ficient space in the lost+found directory, its size is increased.
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92       An attempt to mount a ufs file system with the -o  nolargefiles  option
93       will  fail  if  the file system has ever contained a large file (a file
94       whose size is greater than or equal to 2 Gbyte). Invoking  fsck  resets
95       the file system state if no large files are present in the file system.
96       A successful mount of the file system after invoking fsck indicates the
97       absence  of  large  files  in  the  file  system. An unsuccessful mount
98       attempt indicates  the  presence  of  at  least  one  large  file.  See
99       mount_ufs(1M).
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OPTIONS

102       The generic-options consist of the following options:
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104       -m          Check  but  do not repair. This option checks that the file
105                   system is suitable for mounting, returning the  appropriate
106                   exit status. If the file system is ready for mounting, fsck
107                   displays a message such as:
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111                       ufs fsck: sanity check: /dev/rdsk/c0t3d0s1 okay
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115       -n|N        Assume a no response to all questions asked by fsck; do not
116                   open the file system for writing.
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119       -V          Echo the expanded command line, but do not execute the com‐
120                   mand. This option may be used to verify and to validate the
121                   command line.
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124       -v          Enables  verbose  output.  Might  not  be  supported by all
125                   filesystem-specific fsck implementations.
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128       -y|Y        Assume a yes response to all questions asked by fsck.
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132       See generic fsck(1M) for the details for specifying special.
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134       -o specific-options    Specify ufs file system specific options.  These
135                              options  can be any combination of the following
136                              separated by commas (with  no  intervening  spa‐
137                              ces).
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139                              b=n    Use  block  n  as the super block for the
140                                     file system. Block 32 is  always  one  of
141                                     the alternate super blocks. Determine the
142                                     location of other super blocks by running
143                                     newfs(1M) with the -Nv options specified.
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146                              f      Force checking of file systems regardless
147                                     of the state of their super  block  clean
148                                     flag.
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151                              p      Check  and fix the file system non-inter‐
152                                     actively ("preen"). Exit  immediately  if
153                                     there  is  a  problem requiring interven‐
154                                     tion. This option is required  to  enable
155                                     parallel file system checking.
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158                              w      Check writable file systems only.
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FILES

163       /etc/vfstab    list of default parameters for each file system
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ATTRIBUTES

167       See attributes(5) for descriptions of the following attributes:
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172       ┌─────────────────────────────┬─────────────────────────────┐
173       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
174       ├─────────────────────────────┼─────────────────────────────┤
175       │Availability                 │SUNWcsu                      │
176       └─────────────────────────────┴─────────────────────────────┘
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SEE ALSO

179       clri(1M),  fsck(1M),  fsdb_ufs(1M),  fsirand(1M),  fstyp(1M), mkfs(1M),
180       mkfs_ufs(1M),  mount_ufs(1M),  mountall(1M),   newfs(1M),   reboot(1M),
181       vfstab(4), attributes(5), largefile(5), ufs(7FS)
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WARNINGS

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

194       It is usually faster to check the character  special  device  than  the
195       block special device.
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198       Running fsck on file systems larger than 2 Gb fails if the user chooses
199       to use the block interface to the device:
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201       fsck /dev/dsk/c?t?d?s?
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205       rather than the raw (character special) device:
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207       fsck /dev/rdsk/c?t?d?s?
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212SunOS 5.11                        2 Aug 2005                      fsck_ufs(1M)
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