config root man

.\"
.\" Copyright (c) 2003 Networks Associates Technology, Inc.
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.\" 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.
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.\" $FreeBSD: release/9.1.0/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 .
.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/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.
.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 .