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diff --git a/sys-utils/fsfreeze.8 b/sys-utils/fsfreeze.8 new file mode 100644 index 0000000..3cd6738 --- /dev/null +++ b/sys-utils/fsfreeze.8 @@ -0,0 +1,89 @@ +.TH FSFREEZE 8 "July 2014" "util-linux" "System Administration" +.SH NAME +fsfreeze \- suspend access to a filesystem (Ext3/4, ReiserFS, JFS, XFS) +.SH SYNOPSIS +.B fsfreeze +.BR \--freeze | \--unfreeze +.I mountpoint + +.SH DESCRIPTION +.B fsfreeze +suspends or resumes access to a filesystem. +.PP +.B fsfreeze +halts any new access to the filesystem and creates a stable image on disk. +.B fsfreeze +is intended to be used with hardware RAID devices that support the creation +of snapshots. +.PP +.B fsfreeze +is unnecessary for +.B device-mapper +devices. The device-mapper (and LVM) automatically freezes a filesystem +on the device when a snapshot creation is requested. +For more details see the +.BR dmsetup (8) +man page. +.PP +The +.I mountpoint +argument is the pathname of the directory where the filesystem +is mounted. +The filesystem must be mounted to be frozen (see +.BR mount (8)). +.PP +Note that access-time updates are also suspended if the filesystem is mounted with +the traditional atime behavior (mount option \fBstrictatime\fR, for more details see +.BR mount (8)). + +.SH OPTIONS +.TP +.BR \-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. +.sp +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. +.TP +.BR \-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. +.TP +.BR \-V , " \-\-version" +Display version information and exit. +.TP +.BR \-h , " \-\-help" +Display help text and exit. +.SH FILESYSTEM SUPPORT +This command will work only if filesystem supports has support for freezing. +List of these filesystems include (2016-12-18) +.BR btrfs , +.BR ext2/3/4 , +.BR f2fs , +.BR jfs , +.BR nilfs2 , +.BR reiserfs , +and +.BR xfs . +Previous list may be incomplete, as more filesystems get support. If in +doubt easiest way to know if a filesystem has support is create a small +loopback mount and test freezing it. +.SH AUTHOR +.PP +Written by Hajime Taira. +.SH NOTES +.PP +This man page is based on +.BR xfs_freeze (8). +.SH SEE ALSO +.BR mount (8) +.SH AVAILABILITY +The fsfreeze command is part of the util-linux package and is available from +https://www.kernel.org/pub/linux/utils/util-linux/. |