xref: /dflybsd-src/share/man/man4/vn.4 (revision 86d7f5d305c6adaa56ff4582ece9859d73106103)
1*86d7f5d3SJohn Marino.\"	$NetBSD: vnd.4,v 1.1 1995/12/30 18:10:48 thorpej Exp $
2*86d7f5d3SJohn Marino.\"
3*86d7f5d3SJohn Marino.\" Copyright (c) 1995 Jason R. Thorpe.
4*86d7f5d3SJohn Marino.\" All rights reserved.
5*86d7f5d3SJohn Marino.\"
6*86d7f5d3SJohn Marino.\" Redistribution and use in source and binary forms, with or without
7*86d7f5d3SJohn Marino.\" modification, are permitted provided that the following conditions
8*86d7f5d3SJohn Marino.\" are met:
9*86d7f5d3SJohn Marino.\" 1. Redistributions of source code must retain the above copyright
10*86d7f5d3SJohn Marino.\"    notice, this list of conditions and the following disclaimer.
11*86d7f5d3SJohn Marino.\" 2. Redistributions in binary form must reproduce the above copyright
12*86d7f5d3SJohn Marino.\"    notice, this list of conditions and the following disclaimer in the
13*86d7f5d3SJohn Marino.\"    documentation and/or other materials provided with the distribution.
14*86d7f5d3SJohn Marino.\" 3. All advertising materials mentioning features or use of this software
15*86d7f5d3SJohn Marino.\"    must display the following acknowledgement:
16*86d7f5d3SJohn Marino.\"	This product includes software developed for the NetBSD Project
17*86d7f5d3SJohn Marino.\"	by Jason R. Thorpe.
18*86d7f5d3SJohn Marino.\" 4. Neither the name of the author nor the names of its contributors
19*86d7f5d3SJohn Marino.\"    may be used to endorse or promote products derived from this software
20*86d7f5d3SJohn Marino.\"    without specific prior written permission.
21*86d7f5d3SJohn Marino.\"
22*86d7f5d3SJohn Marino.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23*86d7f5d3SJohn Marino.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24*86d7f5d3SJohn Marino.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25*86d7f5d3SJohn Marino.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26*86d7f5d3SJohn Marino.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
27*86d7f5d3SJohn Marino.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28*86d7f5d3SJohn Marino.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29*86d7f5d3SJohn Marino.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30*86d7f5d3SJohn Marino.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31*86d7f5d3SJohn Marino.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32*86d7f5d3SJohn Marino.\" SUCH DAMAGE.
33*86d7f5d3SJohn Marino.\"
34*86d7f5d3SJohn Marino.\" $FreeBSD: src/share/man/man4/vn.4,v 1.6.2.4 2002/04/15 05:48:55 asmodai Exp $
35*86d7f5d3SJohn Marino.\" $DragonFly: src/share/man/man4/vn.4,v 1.6 2007/06/14 21:16:13 swildner Exp $
36*86d7f5d3SJohn Marino.\"
37*86d7f5d3SJohn Marino.Dd September 28, 2009
38*86d7f5d3SJohn Marino.Dt VN 4
39*86d7f5d3SJohn Marino.Os
40*86d7f5d3SJohn Marino.Sh NAME
41*86d7f5d3SJohn Marino.Nm vn
42*86d7f5d3SJohn Marino.Nd vnode disk driver
43*86d7f5d3SJohn Marino.Sh SYNOPSIS
44*86d7f5d3SJohn Marino.Cd pseudo-device vn Op n
45*86d7f5d3SJohn Marino.Pp
46*86d7f5d3SJohn MarinoAlternatively, to load the driver as a module at boot time, place the
47*86d7f5d3SJohn Marinofollowing line in
48*86d7f5d3SJohn Marino.Pa /boot/loader.conf :
49*86d7f5d3SJohn Marino.Bd -literal -offset indent
50*86d7f5d3SJohn Marinovn_load="YES"
51*86d7f5d3SJohn Marino.Ed
52*86d7f5d3SJohn Marino.Sh DESCRIPTION
53*86d7f5d3SJohn MarinoThe
54*86d7f5d3SJohn Marino.Nm
55*86d7f5d3SJohn Marinodriver uses swap or a file as backing store to abstract-out a
56*86d7f5d3SJohn Marinodevice which may then be used like a disk.
57*86d7f5d3SJohn MarinoThe
58*86d7f5d3SJohn Marino.Nm
59*86d7f5d3SJohn Marinodriver supports both labeled and unlabeled pseudo-disks and is useful for
60*86d7f5d3SJohn Marinoa variety of applications, including swap files and building mini-root,
61*86d7f5d3SJohn Marinofloppy, or CD-ROM disk images.
62*86d7f5d3SJohn Marino.Nm
63*86d7f5d3SJohn Marinomay also be used to create temporary swap-backed filesystems, such as
64*86d7f5d3SJohn Marino.Pa /tmp ,
65*86d7f5d3SJohn Marinoin a somewhat less memory-hungry manner than MFS.
66*86d7f5d3SJohn Marino.Pp
67*86d7f5d3SJohn MarinoThe
68*86d7f5d3SJohn Marino.Nm
69*86d7f5d3SJohn Marinodriver supports autocloning. By default 4
70*86d7f5d3SJohn Marino.Nm
71*86d7f5d3SJohn Marinodevices are also precreated.
72*86d7f5d3SJohn Marino.Sh FILES
73*86d7f5d3SJohn Marino.Bl -tag -width "Pa /dev/vn*" -compact
74*86d7f5d3SJohn Marino.It Pa /dev/vn*
75*86d7f5d3SJohn Marino.Nm
76*86d7f5d3SJohn Marinodevice special files
77*86d7f5d3SJohn Marino.El
78*86d7f5d3SJohn Marino.Sh SEE ALSO
79*86d7f5d3SJohn Marino.Xr fsck 8 ,
80*86d7f5d3SJohn Marino.Xr mount 8 ,
81*86d7f5d3SJohn Marino.Xr mount_mfs 8 ,
82*86d7f5d3SJohn Marino.Xr newfs 8 ,
83*86d7f5d3SJohn Marino.Xr vnconfig 8
84*86d7f5d3SJohn Marino.Sh HISTORY
85*86d7f5d3SJohn MarinoThe vnode disk driver was originally written at the University of
86*86d7f5d3SJohn MarinoUtah and was substantially modified by
87*86d7f5d3SJohn Marino.Fx
88*86d7f5d3SJohn Marinodevelopers to add swap-backed support.
89*86d7f5d3SJohn Marino.Sh BUGS
90*86d7f5d3SJohn MarinoThe
91*86d7f5d3SJohn Marino.Nm
92*86d7f5d3SJohn Marinodriver does not work if the file does not reside in a local filesystem.
93