Copyright (c) 2003 Networks Associates Technology, Inc.
All rights reserved.
This software was developed for the FreeBSD Project by Marshall
Kirk McKusick and Network Associates Laboratories, the Security
Research Division of Network Associates, Inc. under DARPA/SPAWAR
contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
research program.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. The names of the authors may not be used to endorse or promote
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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$FreeBSD: head/sbin/mksnap_ffs/mksnap_ffs.8 218700 2011-02-15 07:25:54Z keramida $
.Dd February 14, 2011 .Dt MKSNAP_FFS 8 .Os .Sh NAME .Nm mksnap_ffs .Nd take a file system snapshot .Sh SYNOPSIS .Nm .Ar snapshot_name .Sh DESCRIPTION The .Nm utility creates a snapshot named .Ar snapshot_name .
p The group ownership of the file is set to .Dq Li operator ; the owner of the file remains .Dq Li root . The mode of the snapshot is set to be readable by the owner or members of the .Dq Li operator group. .Sh EXAMPLES Create a snapshot of
a /usr/home file system and mount the snapshot elsewhere: d -literal -offset indent mksnap_ffs /usr/home/snapshot mdconfig -a -t vnode -o readonly -f /usr/home/snapshot mount -o ro /dev/md0 /mnt/ .Ed .Sh SEE ALSO .Xr chmod 2 , .Xr chown 8 , .Xr mdconfig 8 , .Xr mount 8 .Sh HISTORY The .Nm utility first appeared in .Fx 5.0 . .Sh CAVEATS The disk full situation is not handled gracefully and may lead to a system panic when no free blocks are found.
p Every filesystem can have only up to 20 active snapshots. When this limit is reached, attempting to create more snapshots fails with .Er ENOSPC , and .Nm reports that it is .Dq out of space .