FSFREEZE(8) System Administration FSFREEZE(8)

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

SYNOPSIS fsfreeze -f mountpoint

fsfreeze -u 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)).

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 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 con- tain information on files that are still in the process of unlinking. These files will not be unlinked until the filesys- tem is unfrozen or a clean mount of the snapshot is complete.

-u, --unfreeze This option is used to un-freeze the filesystem and allow opera- tions to continue. Any filesystem modifications that were blocked by the freeze are unblocked and allowed to complete.

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)