Manual: fsfreeze

FSFREEZE(8)					    System Administration					 FSFREEZE(8)

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

SYNOPSIS
       fsfreeze --freeze|--unfreeze mountpoint

DESCRIPTION
       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
       -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
	   Display version and exit.

FILESYSTEM SUPPORT
       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
       This man page is based on xfs_freeze(8).

AUTHORS
       Written by Hajime Taira.

SEE ALSO
       mount(8)

REPORTING BUGS
       For bug reports, use the issue tracker .

AVAILABILITY
       The fsfreeze command is part of the util-linux package which can be downloaded from Linux Kernel Archive
       .

util-linux 2.41.3					 2025-12-15						 FSFREEZE(8)