2 .\" Copyright (c) 2003 Networks Associates Technology, Inc.
3 .\" All rights reserved.
5 .\" This software was developed for the FreeBSD Project by Marshall
6 .\" Kirk McKusick and Network Associates Laboratories, the Security
7 .\" Research Division of Network Associates, Inc. under DARPA/SPAWAR
8 .\" contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
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15 .\" notice, this list of conditions and the following disclaimer.
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19 .\" 3. The names of the authors may not be used to endorse or promote
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23 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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42 .Nd take a file system snapshot
49 utility creates a snapshot named
52 The group ownership of the file is set to
54 the owner of the file remains
56 The mode of the snapshot is set to be readable by the owner
63 file system and mount the snapshot elsewhere:
64 .Bd -literal -offset indent
65 mksnap_ffs /usr/home/snapshot
66 mdconfig -a -t vnode -o readonly -f /usr/home/snapshot
67 mount -o ro /dev/md0 /mnt/
77 utility first appeared in
80 The disk full situation is not handled gracefully and may
81 lead to a system panic when no free blocks are found.
83 Every filesystem can have only up to 20 active snapshots.
84 When this limit is reached, attempting to create more snapshots