1.\" Copyright (c) 1993 University of Utah. 2.\" Copyright (c) 1980, 1989, 1991, 1993 3.\" The Regents of the University of California. All rights reserved. 4.\" 5.\" This code is derived from software contributed to Berkeley by 6.\" the Systems Programming Group of the University of Utah Computer 7.\" Science Department. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the University of 20.\" California, Berkeley and its contributors. 21.\" 4. Neither the name of the University nor the names of its contributors 22.\" may be used to endorse or promote products derived from this software 23.\" without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35.\" SUCH DAMAGE. 36.\" 37.\" @(#)vnconfig.8 8.1 (Berkeley) 6/5/93 38.\" $FreeBSD: src/usr.sbin/vnconfig/vnconfig.8,v 1.14.2.8 2003/01/04 22:35:53 keramida Exp $ 39.\" $DragonFly: src/usr.sbin/vnconfig/vnconfig.8,v 1.10 2008/07/27 22:36:01 thomas Exp $ 40.\" 41.Dd January 30, 2008 42.Dt VNCONFIG 8 43.Os 44.Sh NAME 45.Nm vnconfig 46.Nd configure and enable vnode disks 47.Sh SYNOPSIS 48.Nm 49.Op Fl cdeguvTZ 50.Op Fl s Ar options 51.Op Fl r Ar options 52.Op Fl S Ar value 53.Ar special_file Op Ar regular_file 54.Op Ar feature 55.Nm 56.Fl a 57.Op Fl cdeguv 58.Op Fl s Ar options 59.Op Fl r Ar options 60.Op Fl f Ar config_file 61.Nm 62.Fl l 63.Op Ar special_file Ar ... 64.Sh DESCRIPTION 65The 66.Nm 67command configures, enables and lists vnode pseudo disk devices. 68The first form of the command will associate the special file 69.Ar special_file 70with the regular file 71.Ar regular_file 72allowing the latter to be accessed as though it were a disk. 73Hence a regular file within the filesystem can be used for swapping 74or can contain a filesystem that is mounted in the name space. If you 75want to use swap backing store for your device instead of a file, you 76can leave 77.Ar regular_file 78out and specify the size of the block device 79with the 80.Fl S 81option. 82.Pp 83Options indicate an action to be performed: 84.Bl -tag -width indent 85.It Fl a 86Read a command file and performs the 87specified actions for each device/file pair. 88.It Fl c 89Configure the device. 90If successful, references to 91.Ar special_file 92will access the contents of 93.Ar regular_file . 94.It Fl d 95Disable (if possible) the specified feature. 96.It Fl e 97Configure the device and enables any 98.Ar feature 99that was specified. 100If no feature was specified, 101.Fl e 102is the same as 103.Fl c . 104.It Fl f Ar config_file 105Use 106.Ar config_file 107as an alternate config file. 108.It Fl g 109Fiddle global options. 110.It Fl l Ar special_file Ar ... 111List the VN devices and indicate which ones are in use. 112If a 113.Ar special_file 114list is given, only those devices will be described. 115.It Fl r Ar options 116Reset 117.Ar options , 118which is a comma separated string of options. 119The list of allowed options and their meanings are: 120.Bl -tag -width "follow" 121.It Ar labels 122use disk/slice labels. 123.It Ar reserve 124Pre-reserve the blocks underlying the file or swap backing store. Currently only 125works for swap backing store. This option also disables on-the-fly freeing of 126the underlying backing store (for example, when you remove a large file). 127Use this option if you wish to avoid long-term fragmentation of the backing 128store. Also note that when this option is used, the initial contents of the 129backing store may contain garbage rather than zeros. It may even be possible to 130recover the prior contents of a swap-backed VN across a reboot if the VN device 131is configured before any swap is allocated by the system. 132.It Ar follow 133debug flow in the 134.Xr vn 4 135driver. 136.It Ar debug 137debug data in the 138.Xr vn 4 139driver. 140.It Ar io 141debug I/O in the 142.Xr vn 4 143driver. 144.It Ar all 145turn on all options. 146.It Ar none 147turn off all options. 148.El 149.It Fl s Ar options 150Set 151.Ar options , 152which is a comma separated string of options. 153The list of allowed options and their meanings are the same as for the 154.Fl r 155option. 156.It Fl S Xo 157.Sm off 158.Ar value 159.Es \&{ \&} 160.En Cm k , m , g , t 161.Sm on 162.Xc 163If no regular file is specified, VN will use swap for backing store. 164This option specifies the size of the device. For example, 165.Sq 23m 166for 16723 megabytes. The VN device will round the size up to a machine page boundary. 168Filesystems up to 7.9 terabytes are supported. When specified along with 169a regular file, this option overrides the regular file's size insofar as 170VN is concerned. 171.It Fl T 172When a regular file is specified, VN will 173.Fn ftruncate 174the file to length 0 first. 175Normally you should also specify the 176.Fl S 177option to set the size of the file. 178This option also creates the file if it did not previously exist. 179This option is only meaningful if the 180.Fl S 181option has been specified. 182.It Fl Z 183When a regular file is specified, VN will zero the contents of the file to 184ensure that all blocks have been allocated by the filesystem. This option is 185only meaningful if the 186.Fl S 187option has been specified. 188.It Fl u 189Disable and ``unconfigure'' the device. 190.It Fl v 191Print messages to stdout describing actions taken. 192.El 193.Pp 194If no action option is given, 195.Fl c 196is assumed. 197.Pp 198The 199.Ar feature 200argument specifies a feature that can be enabled via the 201.Fl e 202option: 203.Bl -tag -width indent 204.It Dv swap 205Swapping is enabled on the special file. 206See 207.Xr swapon 2 . 208.It Dv mountro Ns = Ns Pa mount_point 209The special file is mounted read-only on 210.Ar mount_point . 211See 212.Xr mount 2 . 213.It Dv mountrw Ns = Ns Pa mount_point 214The special file is mounted read-write on 215.Ar mount_point . 216See 217.Xr mount 2 . 218.It Dv mount Ns = Ns Pa mount_point 219Same as ``mountrw=''. 220.El 221.Pp 222A configuration file contains one line per device/file pair in the form: 223.Bd -literal 224 special_file regular_file [ feature ] 225.Ed 226.Pp 227where fields are separated by white space. 228The previously described action options serve to configure, enable, 229disable or unconfigure all devices in the configuration file. 230.Sh FILES 231.Bl -tag -width /etc/vntab -compact 232.It Pa /etc/vntab 233default configuration file for 234.Fl a 235option 236.El 237.Sh EXAMPLES 238.Dl vnconfig vn0 /tmp/diskimage 239.Pp 240Configures the vnode disk 241.Pa vn0 . 242.Pp 243.Dl vnconfig -e vn0 /var/swapfile swap 244.Pp 245Configures 246.Pa vn0 247and enables swapping on it. 248.Pp 249.Dl vnconfig -c -v /dev/vn0 cdimage.iso 250.Dl mount -t cd9660 -o ro /dev/vn0 /mnt 251.Pp 252Mount an ISO9660 CD image file. 253.Pp 254.Dl umount /mnt 255.Dl vnconfig -u vn0 256.Pp 257Unmount the CD image file. 258.Pp 259.Dl vnconfig -d vn0 myfilesystem mount=/mnt 260.Pp 261Unmounts (disables) 262.Pa vn0 . 263.Pp 264.Dl vnconfig -ae 265.Pp 266Configures and enables all devices specified in 267.Pa /etc/vntab . 268.Pp 269.Dl vnconfig -s labels -c vn0 somebackingfile 270.Dl disklabel -r -w vn0s0 auto 271.Dl disklabel -e vn0s0 272.Pp 273Is an example of how to configure a file-backed VN disk with a disk label 274and to initialize and then edit the label. Once you create the label, you 275can partition your VN disk and, for example, create a filesystem on one of 276the partitions. If you are using a file as backing store, it may be possible 277to recover your VN disk after a crash by vnconfig'ing the same file again 278and using the VN configuration already stored in the file rather than 279relabeling and recreating the filesystem. It is even possible to fsck the 280VN partitions that previously contained filesystems. 281.Pp 282.Dl vnconfig -e -s labels,reserve -S 400m vn1 283.Dl disklabel -r -w vn1s0 auto 284.Dl newfs /dev/vn1s0 285.Dl mount /dev/vn1s0 /usr/obj 286.Pp 287Is an example of a swap-backed VN disk configuration. This example assumes 288that you have at least 400 megabytes of swap free (and hopefully much more). 289The swap space is pre-reserved in order to maintain maximum performance. 290We then label the disk, newfs it, and mount it as 291.Pa /usr/obj . 292Swap-backed VN 293devices are recoverable after a crash if you (A) use the reserve option, and if 294(B) the same swap is reserved as was the last time, meaning that such 295vnconfig's would have to be run in your rc.local. In general, though, you 296only use swap-backed VN devices to hold information you don't mind losing 297on every reboot. 298.Sh SEE ALSO 299.Xr mount 2 , 300.Xr swapon 2 , 301.Xr unmount 2 , 302.Xr vn 4 303