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

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

9       fsfreeze --freeze|--unfreeze mountpoint
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DESCRIPTION

12       fsfreeze suspends or resumes access to a filesystem.
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14       fsfreeze halts any new access to the filesystem and creates a stable
15       image on disk. fsfreeze is intended to be used with hardware RAID
16       devices that support the creation of snapshots.
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18       fsfreeze is unnecessary for device-mapper devices. The device-mapper
19       (and LVM) automatically freezes a filesystem on the device when a
20       snapshot creation is requested. For more details see the dmsetup(8) man
21       page.
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23       The mountpoint argument is the pathname of the directory where the
24       filesystem is mounted. The filesystem must be mounted to be frozen (see
25       mount(8)).
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27       Note that access-time updates are also suspended if the filesystem is
28       mounted with the traditional atime behavior (mount option strictatime,
29       for more details see mount(8)).
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OPTIONS

32       -f, --freeze
33           This option requests the specified filesystem to be frozen from new
34           modifications. When this is selected, all ongoing transactions in
35           the filesystem are allowed to complete, new write(2) system calls
36           are halted, other calls which modify the filesystem are halted, and
37           all dirty data, metadata, and log information are written to disk.
38           Any process attempting to write to the frozen filesystem will block
39           waiting for the filesystem to be unfrozen.
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41           Note that even after freezing, the on-disk filesystem can contain
42           information on files that are still in the process of unlinking.
43           These files will not be unlinked until the filesystem is unfrozen
44           or a clean mount of the snapshot is complete.
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46       -u, --unfreeze
47           This option is used to un-freeze the filesystem and allow
48           operations to continue. Any filesystem modifications that were
49           blocked by the freeze are unblocked and allowed to complete.
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51       -h, --help
52           Display help text and exit.
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54       -V, --version
55           Print version and exit.
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FILESYSTEM SUPPORT

58       This command will work only if filesystem supports has support for
59       freezing. List of these filesystems include (2016-12-18) btrfs,
60       ext2/3/4, f2fs, jfs, nilfs2, reiserfs, and xfs. Previous list may be
61       incomplete, as more filesystems get support. If in doubt easiest way to
62       know if a filesystem has support is create a small loopback mount and
63       test freezing it.
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NOTES

66       This man page is based on xfs_freeze(8).
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AUTHORS

69       Written by Hajime Taira.
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SEE ALSO

72       mount(8)
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REPORTING BUGS

75       For bug reports, use the issue tracker at
76       https://github.com/util-linux/util-linux/issues.
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AVAILABILITY

79       The fsfreeze command is part of the util-linux package which can be
80       downloaded from Linux Kernel Archive
81       <https://www.kernel.org/pub/linux/utils/util-linux/>.
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85util-linux 2.38                   2022-02-17                       FSFREEZE(8)
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