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 https://www.kernel.org/pub/linux/utils/util-linux/.

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
       2020-11-01.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-10-21.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
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       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)