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.
The fsfreeze command is part of the util-linux package which can
be downloaded from Linux Kernel Archive
<https://www.kernel.org/pub/linux/utils/util-linux/>. 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
email@example.com. This page was obtained from the
project's upstream Git repository
2021-08-27. (At that time, the date of the most recent commit
that was found in the repository was 2021-08-24.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in
this COLOPHON (which is not part of the original manual page),
send a mail to firstname.lastname@example.org
util-linux 2.37.85-637cc 2021-04-02 FSFREEZE(8)