FSFREEZE(8)                           System Administration                           FSFREEZE(8)



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) automati‐
       cally 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 modifica‐
              tions.  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.

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
       ftp://ftp.kernel.org/pub/linux/utils/util-linux/.




util-linux                                  July 2014                                 FSFREEZE(8)