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)
The mountpoint argument is the pathname of the directory where the
filesystem is mounted. The filesystem must be mounted to be frozen
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
2020-05-27. (At that time, the date of the most recent commit that
was found in the repository was 2020-05-27.) 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
util-linux July 2014 FSFREEZE(8)