fsfreeze(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILESYSTEM SUPPORT | NOTES | AUTHORS | SEE ALSO | REPORTING BUGS | AVAILABILITY

FSFREEZE(8)               System Administration               FSFREEZE(8)

NAME         top

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

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
           complete.

       -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 complete.

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

       -V, --version
           Print version and exit.

FILESYSTEM SUPPORT         top

       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

       mount(8)

REPORTING BUGS         top

       For bug reports, use the issue tracker
       <https://github.com/util-linux/util-linux/issues>.

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
       2025-02-02. (At that time, the date of the most recent commit that
       was found in the repository was 2025-01-30.) 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 2.41.devel-938-0a... 2025-01-15                    FSFREEZE(8)