FSFREEZE(8) System Administration FSFREEZE(8)
fsfreeze - suspend access to a filesystem (Ext3/4, ReiserFS, JFS, XFS)
fsfreeze --freeze|--unfreeze mountpoint
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 snap-
shot creation is requested. For more details see the dmsetup(8) man
The mountpoint argument is the pathname of the directory where the
filesystem is mounted. The filesystem must be mounted to be frozen
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)).
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 con-
tain information on files that are still in the process of
unlinking. These files will not be unlinked until the filesys-
tem is unfrozen or a clean mount of the snapshot is complete.
This option is used to un-freeze the filesystem and allow opera-
tions to continue. Any filesystem modifications that were
blocked by the freeze are unblocked and allowed to complete.
Display version information and exit.
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.
Written by Hajime Taira.
This man page is based on xfs_freeze(8).
The fsfreeze command is part of the util-linux package and is available
util-linux July 2014 FSFREEZE(8)
Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2022
All Rights Reserved.