diff --git a/sbin/mksnap_ffs/mksnap_ffs.8 b/sbin/mksnap_ffs/mksnap_ffs.8 index 6274e93a4adb..2bba68150636 100644 --- a/sbin/mksnap_ffs/mksnap_ffs.8 +++ b/sbin/mksnap_ffs/mksnap_ffs.8 @@ -1,107 +1,108 @@ .\" .\" 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 .\" products derived from this software without specific prior written .\" permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd March 5, 2023 .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 . This name is a path in the file system to be snapshotted. Typically this is under the .Pa .snap directory in the root of the file system, but it can be anywhere in the filesystem being snapshotted. Snapshots can be listed using the .Xr snapinfo 8 command. .Pp After a snapshot is taken it appears as a file. -The file is the size of the file system from which it was taken. +The size of the snapshot file is equal to the size of the +file system from which it was taken. It can be moved, renamed or deleted (which removes the snapshot). .Pp 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 .Pa /usr/home file system and mount the snapshot elsewhere: .Bd -literal -offset indent mksnap_ffs /usr/home/.snap/snap1 mdconfig -a -t vnode -o readonly -f /usr/home/.snap/snap1 mount -o ro /dev/md0 /mnt/ .Ed .Pp Delete a snapshot: .Bd -literal -offset indent rm /usr/home/.snap/snap1 .Ed .Sh SEE ALSO .Xr rm 1 , .Xr chmod 2 , .Xr chown 8 , .Xr mdconfig 8 , .Xr mount 8 , .Xr snapinfo 8 .Sh HISTORY The .Nm utility first appeared in .Fx 5.1 . .Sh CAVEATS The disk full situation is not handled gracefully and may lead to a system panic when no free blocks are found. .Pp 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 .