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 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

       -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

       -V, --version
              Display version information and exit.

       -h, --help
              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.

NOTES         top

       This man page is based on xfs_freeze(8).

AUTHORS         top

       Written by Hajime Taira.

SEE ALSO         top


AVAILABILITY         top

       The fsfreeze command is part of the util-linux package and is
       available from

COLOPHON         top

       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
       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,
       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                      July 2014                    FSFREEZE(8)