1FSFREEZE(8)                  System Administration                 FSFREEZE(8)
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NAME

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

10       fsfreeze --freeze|--unfreeze mountpoint
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DESCRIPTION

14       fsfreeze suspends and resumes access to an filesystem
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16       fsfreeze halts new access to the filesystem and creates a stable  image
17       on  disk.   fsfreeze  is intended to be used with hardware RAID devices
18       that support the creation of snapshots.
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20       fsfreeze is unnecessary for device-mapper  devices.  The  device-mapper
21       (and  LVM)  automatically freezes filesystem on the device when a snap‐
22       shot creation is requested.  For more details see  the  dmsetup(8)  man
23       page.
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25       The  mount-point  argument  is  the pathname of the directory where the
26       filesystem is mounted.  The filesystem must be  mounted  to  be  frozen
27       (see mount(8)).
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29       Note  that  access  time updates are also suspends if the filesystem is
30       mounted with the traditional atime semantics (mount option strictatime,
31       for more details see mount(8)).
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OPTIONS

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

62       Written by Hajime Taira.
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NOTES

65       This man page based on xfs_freeze.  One of -f or -u must be supplied to
66       fsfreeze.
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SEE ALSO

69       mount(8)
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AVAILABILITY

72       The fsfreeze command is part of the util-linux package and is available
73       from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
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78util-linux                         May 2010                        FSFREEZE(8)
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