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. fsfreeze
is intended to be used with hardware RAID
devices that support the creation of snapshots.
is unnecessary for device-mapper
device-mapper (and LVM) automatically freezes a filesystem on the device when
a snapshot creation is requested. For more details see the dmsetup
argument is the pathname of the directory where the
filesystem is mounted. 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 mount
- -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) btrfs
, 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
The fsfreeze command is part of the util-linux package and is available from