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       xfs_freeze - suspend access to an XFS filesystem


       xfs_freeze -f | -u mount-point


       xfs_freeze  suspends  and  resumes  access  to  an  XFS filesystem (see

       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 creation 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 complete.

       One of -f or -u must be supplied to xfs_freeze.


       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 elevated to the VFS, so that this tool can now be used
       on many other Linux filesystems.


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