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 reserve 122Pre-reserve the blocks underlying the file or swap backing store. Currently only 123works for swap backing store. This option also disables on-the-fly freeing of 124the underlying backing store (for example, when you remove a large file). 125Use this option if you wish to avoid long-term fragmentation of the backing 126store. Also note that when this option is used, the initial contents of the 127backing store may contain garbage rather than zeros. It may even be possible to 128recover the prior contents of a swap-backed VN across a reboot if the VN device 129is configured before any swap is allocated by the system. 130.It Ar follow 131debug flow in the 132.Xr vn 4 133driver. 134.It Ar debug 135debug data in the 136.Xr vn 4 137driver. 138.It Ar io 139debug I/O in the 140.Xr vn 4 141driver. 142.It Ar all 143turn on all options. 144.It Ar none 145turn off all options. 146.El 147.It Fl s Ar options 148Set 149.Ar options , 150which is a comma separated string of options. 151The list of allowed options and their meanings are the same as for the 152.Fl r 153option. 154.It Fl S Xo 155.Sm off 156.Ar value 157.Es \&{ \&} 158.En Cm k , m , g , t 159.Sm on 160.Xc 161If no regular file is specified, VN will use swap for backing store. 162This option specifies the size of the device. For example, 163.Sq 23m 164for 16523 megabytes. 166In the absence of a size modifier, 167.Cm m 168is implied. 169The VN device will round the size up to a machine page boundary. 170Filesystems up to 7.9 terabytes are supported. When specified along with 171a regular file, this option overrides the regular file's size insofar as 172VN is concerned. 173.It Fl T 174When a regular file is specified, VN will 175.Fn ftruncate 176the file to length 0 first. 177Normally you should also specify the 178.Fl S 179option to set the size of the file. 180This option also creates the file if it did not previously exist. 181This option is only meaningful if the 182.Fl S 183option has been specified. 184.It Fl Z 185When a regular file is specified, VN will zero the contents of the file to 186ensure that all blocks have been allocated by the filesystem. This option is 187only meaningful if the 188.Fl S 189option has been specified. 190.It Fl u 191Disable and ``unconfigure'' the device. 192.It Fl v 193Print messages to stdout describing actions taken. 194.El 195.Pp 196If no action option is given, 197.Fl c 198is assumed. 199.Pp 200The 201.Ar feature 202argument specifies a feature that can be enabled via the 203.Fl e 204option: 205.Bl -tag -width indent 206.It Dv swap 207Swapping is enabled on the special file. 208See 209.Xr swapon 2 . 210.It Dv mountro Ns = Ns Pa mount_point 211The special file is mounted read-only on 212.Ar mount_point . 213See 214.Xr mount 2 . 215.It Dv mountrw Ns = Ns Pa mount_point 216The special file is mounted read-write on 217.Ar mount_point . 218See 219.Xr mount 2 . 220.It Dv mount Ns = Ns Pa mount_point 221Same as ``mountrw=''. 222.El 223.Pp 224A configuration file contains one line per device/file pair in the form: 225.Bd -literal 226 special_file regular_file [ feature ] 227.Ed 228.Pp 229where fields are separated by white space. 230The previously described action options serve to configure, enable, 231disable or unconfigure all devices in the configuration file. 232.Sh FILES 233.Bl -tag -width /etc/vntab -compact 234.It Pa /etc/vntab 235default configuration file for 236.Fl a 237option 238.El 239.Sh EXAMPLES 240.Dl vnconfig vn0 /tmp/diskimage 241.Pp 242Configures the vnode disk 243.Pa vn0 . 244.Pp 245.Dl vnconfig -e vn0 /var/swapfile swap 246.Pp 247Configures 248.Pa vn0 249and enables swapping on it. 250.Pp 251.Dl vnconfig -c -v /dev/vn0 cdimage.iso 252.Dl mount -t cd9660 -o ro /dev/vn0 /mnt 253.Pp 254Mount an ISO9660 CD image file. 255.Pp 256.Dl umount /mnt 257.Dl vnconfig -u vn0 258.Pp 259Unmount the CD image file. 260.Pp 261.Dl vnconfig -d vn0 myfilesystem mount=/mnt 262.Pp 263Unmounts (disables) 264.Pa vn0 . 265.Pp 266.Dl vnconfig -ae 267.Pp 268Configures and enables all devices specified in 269.Pa /etc/vntab . 270.Pp 271.Dl vnconfig -c vn0 somebackingfile 272.Dl disklabel -r -w vn0s0 auto 273.Dl disklabel -e vn0s0 274.Pp 275Is an example of how to configure a file-backed VN disk with a disk label 276and to initialize and then edit the label. Once you create the label, you 277can partition your VN disk and, for example, create a filesystem on one of 278the partitions. If you are using a file as backing store, it may be possible 279to recover your VN disk after a crash by vnconfig'ing the same file again 280and using the VN configuration already stored in the file rather than 281relabeling and recreating the filesystem. It is even possible to fsck the 282VN partitions that previously contained filesystems. 283.Pp 284.Dl vnconfig -e -s reserve -S 400m vn1 285.Dl disklabel -r -w vn1s0 auto 286.Dl newfs /dev/vn1s0 287.Dl mount /dev/vn1s0 /usr/obj 288.Pp 289Is an example of a swap-backed VN disk configuration. This example assumes 290that you have at least 400 megabytes of swap free (and hopefully much more). 291The swap space is pre-reserved in order to maintain maximum performance. 292We then label the disk, newfs it, and mount it as 293.Pa /usr/obj . 294Swap-backed VN 295devices are recoverable after a crash if you (A) use the reserve option, and if 296(B) the same swap is reserved as was the last time, meaning that such 297vnconfig's would have to be run in your rc.local. In general, though, you 298only use swap-backed VN devices to hold information you don't mind losing 299on every reboot. 300.Sh SEE ALSO 301.Xr mount 2 , 302.Xr swapon 2 , 303.Xr unmount 2 , 304.Xr vn 4 305