NAME

       fsck.gfs2 - Offline GFS and GFS2 file system checker

SYNOPSIS

       fsck.gfs2 [OPTION]... DEVICE

WARNING

       All  computers  must  have  the filesystem unmounted before running fsck.gfs2.  Failure to
       unmount from all nodes in a cluster will likely result in filesystem corruption.

DESCRIPTION

       fsck.gfs2 will check that the GFS or GFS2 file system on a device is  structurally  valid.
       It  should not be run on a mounted file system.  If file system corruption is detected, it
       will attempt to repair the file system.  There is a limit to what fsck.gfs2  can  do.   If
       important  file  system  structures  are destroyed, such that the checker cannot determine
       what the repairs should be, reparations could fail.

       GFS2 is a journaled file system, and as such should be able to repair damage to  the  file
       system on its own.  However, faulty hardware has the ability to write incomplete blocks to
       a file system thereby causing corruption that GFS2 cannot fix.  The first step to ensuring
       a  healthy  file  system  is the selection of reliable hardware (i.e. storage systems that
       will write complete blocks - even in the event of power failure).

       Note: Most file system checkers will not check the file system  if  it  is  "clean"  (i.e.
       unmounted  since  the  last  use).   The  fsck.gfs program behaves differently because the
       storage may be shared among several nodes in a cluster, and therefore  problems  may  have
       been  introduced on a different computer.  Therefore, fsck.gfs2 will always check the file
       system unless the -p (preen) option is used, in which case it follows special  rules  (see
       below).

       fsck.gfs2   will  log  to  the  system  log  on  start  and  exit  to  aid  debugging  and
       administration.

OPTIONS

       -a     Same as the -p (preen) option.

       -f     Force checking even if the file system seems clean.

       -h     Help.

              This prints out the proper command line usage syntax.

       -q     Quiet.

       -n     No to all questions.

              By specifying this option, fsck.gfs2 will only show the changes that would be made,
              but not make any changes to the filesystem.

       -p     Preen (same as -a: automatically repair the file system if it is dirty, and safe to
              do so, otherwise exit.)

              Note: If the file system has locking  protocol  lock_nolock,  the  file  system  is
              considered  a  non-shared  storage  device  and  the fsck is deemed safe.  However,
              fsck.gfs2 does not know whether it was called automatically from the init  process,
              due  to  options  in  the  /etc/fstab  file.  Therefore, if the locking protocol is
              lock_dlm and -a or -p was specified, fsck.gfs2 cannot determine whether the disk is
              mounted  by other nodes in the cluster.  Therefore, the fsck is deemed to be unsafe
              and a warning is given if any damage or dirty journals are found.   In  that  case,
              the  file  system  should  be unmounted from all nodes in the cluster and fsck.gfs2
              should be run manually without the -a or -p options.

       -V     Version.

              Print out the program version information.

       -v     Verbose operation.

              Print more information while running.

       -y     Yes to all questions.

              By specifying this option, fsck.gfs2 will not prompt before making changes.

                                                                                     fsck.gfs2(8)