man > xfs_freeze(8)

xfs_freeze(8)                          System Manager's Manual                         xfs_freeze(8)

NAME
       xfs_freeze - suspend access to an XFS filesystem

SYNOPSIS
       xfs_freeze [ -f | -u ] mount-point
       xfs_freeze -V

DESCRIPTION
       xfs_freeze suspends and resumes access to an XFS filesystem (see xfs(5)).

       xfs_freeze halts new access to the filesystem and creates a stable image on disk.  xfs_freeze
       is  intended  to be used with volume managers and hardware RAID devices that support the cre‐
       ation of snapshots.

       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)).

       The  -f flag requests the specified XFS 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.

       The -u flag 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 com‐
       plete.

       The -V flag prints the version number and exits.

       Unless -V is specified, one of -f or -u must be supplied to xfs_freeze.

NOTES
       A copy of a frozen XFS filesystem will usually have the same  universally  unique  identifier
       (UUID)  as  the original, and thus may be prevented from being mounted.  The XFS nouuid mount
       option can be used to circumvent this issue.

       In Linux kernel version 2.6.29, the interface which XFS uses to freeze and unfreeze was  ele‐
       vated to the VFS, so that this tool can now be used on many other Linux filesystems.

SEE ALSO
       xfs(5), lvm(8), mount(8).

                                                                                       xfs_freeze(8)