fsfreeze(8) — Linux manual page


FSFREEZE(8)               System Administration              FSFREEZE(8)

NAME         top

       fsfreeze - suspend access to a filesystem (Ext3/4, ReiserFS, JFS,

SYNOPSIS         top

       fsfreeze --freeze|--unfreeze mountpoint

DESCRIPTION         top

       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)).

OPTIONS         top

       -f, --freeze
           This option requests the specified filesystem to be frozen
           from new modifications. When this is selected, all ongoing
           transactions in the filesystem are allowed to complete, new
           write(2) 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

       -u, --unfreeze
           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

       -h, --help
           Display help text and exit.

       -V, --version
           Print version 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.

NOTES         top

       This man page is based on xfs_freeze(8).

AUTHORS         top

       Written by Hajime Taira.

SEE ALSO         top


REPORTING BUGS         top

       For bug reports, use the issue tracker at

AVAILABILITY         top

       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
       util-linux@vger.kernel.org. This page was obtained from the
       project's upstream Git repository
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2023-12-22. (At that time, the date of the most recent commit
       that was found in the repository was 2023-12-14.) 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 man-pages@man7.org

util-linux 2.39.594-1e0ad      2023-07-19                    FSFREEZE(8)