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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILESYSTEM SUPPORT | AUTHOR | NOTES | SEE ALSO | AVAILABILITY | COLOPHON |
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
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)).
-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,
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).
mount(8)
The fsfreeze command is part of the util-linux package and is
available from https://www.kernel.org/pub/linux/utils/util-linux/.
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
2017-07-05. If you discover any rendering problems in this HTML ver‐
sion of the page, or you believe there is a better or more up-to-date
source for the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original man‐
ual page), send a mail to man-pages@man7.org
util-linux July 2014 FSFREEZE(8)