fsfreeze suspends or resumes access to a filesystem.
fsfreeze halts any new access to the filesystem and creates a
stable image on disk. fsfreeze is intended to be used with
hardware RAID devices that support the creation of snapshots.
fsfreeze is unnecessary for device-mapper devices. The device-
mapper (and LVM) automatically freezes a filesystem on the device
when a snapshot creation is requested. For more details see the
dmsetup(8) man page.
The mountpoint argument is the pathname of the directory where
the filesystem is mounted. The filesystem must be mounted to be
frozen (see mount(8)).
Note that access-time updates are also suspended if the
filesystem is mounted with the traditional atime behavior (mount
option strictatime, for more details see mount(8)).
This option requests the specified a filesystem to be
frozen from new modifications. When this is selected, all
ongoing transactions in the filesystem are allowed to
complete, new write system calls are halted, other calls
which modify the filesystem are halted, and all dirty
data, metadata, and log information are written to disk.
Any process attempting to write to the frozen filesystem
will block waiting for the filesystem to be unfrozen.
Note that even after freezing, the on-disk filesystem can
contain information on files that are still in the process
of unlinking. These files will not be unlinked until the
filesystem is unfrozen or a clean mount of the snapshot is
This option is used to un-freeze the filesystem and allow
operations to continue. Any filesystem modifications that
were blocked by the freeze are unblocked and allowed to
Display version information and exit.
Display help text and exit.
This command will work only if filesystem supports has support
for freezing. List of these filesystems include (2016-12-18)
btrfs, ext2/3/4, f2fs, jfs, nilfs2, reiserfs, and xfs. Previous
list may be incomplete, as more filesystems get support. If in
doubt easiest way to know if a filesystem has support is create a
small loopback mount and test freezing it.
This page is part of the util-linux (a random collection of Linux
utilities) project. Information about the project can be found
at ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you
have a bug report for this manual page, send it to
firstname.lastname@example.org. This page was obtained from the
project's upstream Git repository
2021-03-21. (At that time, the date of the most recent commit
that was found in the repository was 2021-03-19.) If you
discover any rendering problems in this HTML version of the page,
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util-linux July 2014 FSFREEZE(8)