76 lines
2.3 KiB
Groff
76 lines
2.3 KiB
Groff
.TH FSFREEZE 8 "July 2014" "util-linux" "System Administration"
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.SH NAME
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fsfreeze \- suspend access to a filesystem (Ext3/4, ReiserFS, JFS, XFS)
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.SH SYNOPSIS
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.B fsfreeze
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.BR \--freeze | \--unfreeze
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.IR mountpoint
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.SH DESCRIPTION
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.B fsfreeze
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suspends or resumes access to a filesystem.
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.PP
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.B fsfreeze
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halts any new access to the filesystem and creates a stable image on disk.
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.B fsfreeze
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is intended to be used with hardware RAID devices that support the creation
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of snapshots.
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.PP
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.B fsfreeze
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is unnecessary for
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.B device-mapper
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devices. The device-mapper (and LVM) automatically freezes a filesystem
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on the device when a snapshot creation is requested.
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For more details see the
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.BR dmsetup (8)
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man page.
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.PP
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The
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.I mountpoint
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argument is the pathname of the directory where the filesystem
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is mounted.
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The filesystem must be mounted to be frozen (see
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.BR mount (8)).
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.PP
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Note that access-time updates are also suspended if the filesystem is mounted with
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the traditional atime behavior (mount option \fBstrictatime\fR, for more details see
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.BR mount (8)).
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.SH OPTIONS
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.TP
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.BR \-f , " \-\-freeze"
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This option requests the specified a filesystem to be frozen from new
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modifications. When this is selected, all ongoing transactions in the
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filesystem are allowed to complete, new write system calls are halted, other
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calls which modify the filesystem are halted, and all dirty data, metadata, and
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log information are written to disk. Any process attempting to write to the
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frozen filesystem will block waiting for the filesystem to be unfrozen.
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.sp
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Note that even after freezing, the on-disk filesystem can contain
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information on files that are still in the process of unlinking.
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These files will not be unlinked until the filesystem is unfrozen
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or a clean mount of the snapshot is complete.
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.TP
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.BR \-u , " \-\-unfreeze"
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This option is used to un-freeze the filesystem and allow operations to
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continue. Any filesystem modifications that were blocked by the freeze are
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unblocked and allowed to complete.
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.TP
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.BR \-V , " \-\-version"
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Display version information and exit.
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.TP
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.BR \-h , " \-\-help"
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Display help text and exit.
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.SH AUTHOR
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.PP
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Written by Hajime Taira.
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.SH NOTES
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.PP
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This man page is based on
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.BR xfs_freeze (8).
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.SH SEE ALSO
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.BR mount (8)
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.SH AVAILABILITY
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The fsfreeze command is part of the util-linux package and is available from
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ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
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