fsfreeze(8)

1FSFREEZE(8)                 System Manager's Manual                FSFREEZE(8)
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NAME

6       fsfreeze  -  suspend  access  to an filesystem (Linux Ext3/4, ReiserFS,
7       JFS, XFS).
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SYNOPSIS

10       fsfreeze -f mountpoint
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12       fsfreeze -u mountpoint
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DESCRIPTION

16       fsfreeze suspends and resumes access to an filesystem
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18       fsfreeze halts new access to the filesystem and creates a stable  image
19       on  disk.   fsfreeze  is intended to be used with hardware RAID devices
20       that support the creation of snapshots.
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22       fsfreeze is unncessary for  device-mapper  devices.  The  device-mapper
23       (and  LVM)  automatically freezes filesystem on the device when a snap‐
24       shot creation is requested.  For more details see  the  dmsetup(8)  man
25       page.
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27       The  mount-point  argument  is  the pathname of the directory where the
28       filesystem is mounted.  The filesystem must be  mounted  to  be  frozen
29       (see mount(8)).
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OPTIONS

32       -h, --help
33              Print help and exit.
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35       -f, --freeze
36              This  option  requests  the  specified a filesystem to be frozen
37              from new modifications.  When  this  is  selected,  all  ongoing
38              transactions  in  the  filesystem  are  allowed to complete, new
39              write system calls are halted,  other  calls  which  modify  the
40              filesystem  are  halted,  and  all dirty data, metadata, and log
41              information are written to  disk.   Any  process  attempting  to
42              write  to  the  frozen  filesystem  will  block  waiting for the
43              filesystem to be unfrozen.
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45              Note that even after freezing, the on-disk filesystem  can  con‐
46              tain  information  on  files  that  are  still in the process of
47              unlinking.  These files will not be unlinked until the  filesys‐
48              tem is unfrozen or a clean mount of the snapshot is complete.
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50       -u, --unfreeze
51              This option is used to un-freeze the filesystem and allow opera‐
52              tions to  continue.   Any  filesystem  modifications  that  were
53              blocked by the freeze are unblocked and allowed to complete.
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AUTHOR

56       Written by Hajime Taira.
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NOTES

59       This man page based on xfs_freeze.  One of -f or -u must be supplied to
60       fsfreeze.
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AVAILABILITY

66       The fsfreeze command is part of the util-linux-ng package and is avail‐
67       able from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
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72                                   May 2010                        FSFREEZE(8)