FSFREEZE(8)						       System Administration						       FSFREEZE(8)

NAME

       fsfreeze - suspend access to a filesystem (Linux Ext3/4, ReiserFS, JFS, XFS)

SYNOPSIS

       fsfreeze --freeze|--unfreeze mountpoint

DESCRIPTION

       fsfreeze suspends and resumes access to an filesystem

       fsfreeze halts 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 filesystem on the device when a  snap-
       shot creation is requested.  For more details see the dmsetup(8) man page.

       The  mount-point  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 suspends if the filesystem is mounted with the traditional atime semantics  (mount  option  stricta-
       time, for more details see mount(8)).

OPTIONS

       -h, --help
	      Print help and exit.

       -f, --freeze
	      This  option  requests  the specified a filesystem to be frozen from new modifications.  When this is selected, all ongoing transac-
	      tions 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
	      Show version number and exit.

AUTHOR

       Written by Hajime Taira.

NOTES

       This man page based on xfs_freeze.  One of -f or -u must be supplied to fsfreeze.

SEE ALSO

       mount(8)

AVAILABILITY

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

util-linux							     May 2010							       FSFREEZE(8)