1fsck.gfs2(8)                System Manager's Manual               fsck.gfs2(8)
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NAME

6       fsck.gfs2 - Offline GFS2 file system checker
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SYNOPSIS

10       fsck.gfs2 [OPTION]... DEVICE
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WARNING

14       All  GFS2  nodes must have the GFS2 filesystem unmounted before running
15       fsck.gfs2.  Failure to unmount all nodes may result in filesystem  cor‐
16       ruption.
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DESCRIPTION

20       fsck.gfs2  will  check  that the GFS2 file system on a device is struc‐
21       turally valid.  It should not be run on a mounted file system.  If file
22       system  corruption is detected, it will attempt to repair the file sys‐
23       tem.  There is a limit to what fsck.gfs2 can  do.   If  important  file
24       system structures are destroyed, such that the checker cannot determine
25       what the repairs should be, reparations could fail.
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27       GFS2 is a journaled file system, and as such should be able  to  repair
28       damage to the file system on its own.  However, faulty hardware has the
29       ability to write incomplete blocks to a  file  system  thereby  causing
30       corruption  that GFS2 cannot fix.  The first step to ensuring a healthy
31       file system is the selection of reliable hardware (i.e. storage systems
32       that will write complete blocks - even in the event of power failure).
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34       Note: Most file system checkers will not check the file system if it is
35       "clean" (i.e. unmounted since the  last  use).   The  fsck.gfs  program
36       behaves  differently  because  the  storage may be shared among several
37       nodes in a cluster, and therefore problems may have been introduced  on
38       a  different computer.  Therefore, fsck.gfs2 will always check the file
39       system unless the -p (preen) option is used, in which case  it  follows
40       special rules (see below).
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OPTIONS

44       -a     Same as the -p (preen) option.
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46       -f     Force checking even if the file system seems clean.
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48       -h     Help.
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50              This prints out the proper command line usage syntax.
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52       -q     Quiet.
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54       -n     No to all questions.
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56              By  specifying this option, fsck.gfs2 will only show the changes
57              that would be made, but not make any changes to the filesystem.
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59       -p     Preen (same as -a: automatically repair the file system if it is
60              dirty, and safe to do so, otherwise exit.)
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62              Note:  If  the file system has locking protocol lock_nolock, the
63              file system is considered a non-shared storage  device  and  the
64              fsck  is  deemed safe.  However, fsck.gfs2 does not know whether
65              it was called  automatically  from  the  init  process,  due  to
66              options  in the /etc/fstab file.  Therefore, if the locking pro‐
67              tocol is lock_dlm and -a or -p was specified,  fsck.gfs2  cannot
68              determine  whether  the  disk  is  mounted by other nodes in the
69              cluster.  Therefore, the fsck is deemed to be unsafe and a warn‐
70              ing is given if any damage or dirty journals are found.  In that
71              case, the file system should be unmounted from all nodes in  the
72              cluster  and  fsck.gfs2 should be run manually without the -a or
73              -p options.
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75       -V     Version.
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77              Print out the program version information.
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79       -v     Verbose operation.
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81              Print more information while running.
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83       -y     Yes to all questions.
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85              By specifying this option, fsck.gfs2 will not prompt before mak‐
86              ing changes.
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