bionic (8) fsfreeze.8.gz

Provided by: util-linux_2.31.1-0.4ubuntu3.7_amd64 bug

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 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.


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.


AUTHOR
       Written by Hajime Taira.


NOTES
       This man page is based on xfs_freeze(8).


SEE ALSO
       mount(8)


AVAILABILITY
       The   fsfreeze   command   is   part   of   the   util-linux    package    and    is    available    from
       https://www.kernel.org/pub/linux/utils/util-linux/.