Section: System Administration (8)
Updated: July 2014
fsfreeze - suspend access to a filesystem (Ext3/4, ReiserFS, JFS, XFS)
suspends or resumes access to a filesystem.
halts any new access to the filesystem and creates a stable image on disk.
is intended to be used with hardware RAID devices that support the creation
is unnecessary for
devices. The device-mapper (and LVM) automatically freezes a filesystem
on the device when a snapshot creation is requested.
For more details see the
argument is the pathname of the directory where the filesystem
The filesystem must be mounted to be frozen (see
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
- -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 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.
- -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)
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
The fsfreeze command is part of the util-linux package and is available from