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 1.9 2008/04/16 07:14:11 swildner 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.Oo Fl s Ar option Ns 51.Op , Ns Ar option Ns Ar ... Oc 52.Oo Fl r Ar option Ns 53.Op , Ns Ar option Ns Ar ... Oc 54.Op Fl S Ar value 55.Ar special_file Op Ar regular_file 56.Op Ar feature 57.Nm 58.Fl a 59.Op Fl cdeguv 60.Op Fl s Ar option 61.Op Fl r Ar option 62.Op Fl f Ar config_file 63.Nm 64.Fl l 65.Op Ar special_file Ar ... 66.Sh DESCRIPTION 67The 68.Nm 69command configures, enables and lists vnode pseudo disk devices. 70The first form of the command will associate the special file 71.Ar special_file 72with the regular file 73.Ar regular_file 74allowing the latter to be accessed as though it were a disk. 75Hence a regular file within the filesystem can be used for swapping 76or can contain a filesystem that is mounted in the name space. If you 77want to use swap backing store for your device instead of a file, you 78can leave regular_file out 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... 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 flag 116Reset 117.Ar flag . 118The list of allowed flags and their meanings are: 119.Bl -tag -width "follow" 120.It Ar labels 121use disk/slice labels. 122.It Ar reserve 123Pre-reserve the blocks underlying the file or swap backing store. Currently only 124works for swap backing store. This option also disables on-the-fly freeing of 125the underlying backing store (for example, when you remove a large file). 126Use this option if you wish to avoid long-term fragmentation of the backing 127store. Also note that when this option is used, the initial contents of the 128backing store may contain garbage rather than zeros. It may even be possible to 129recover the prior contents of a swap-backed VN across a reboot if the VN device 130is configured before any swap is allocated by the system. 131.It Ar follow 132debug flow in the 133.Xr vn 4 134driver. 135.It Ar debug 136debug data in the 137.Xr vn 4 138driver. 139.It Ar io 140debug I/O in the 141.Xr vn 4 142driver. 143.It Ar all 144turn on all flags. 145.It Ar none 146turn off all flags. 147.El 148.It Fl s Ar flag 149Set 150.Ar flag . 151The list of allowed flags 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, '23m' for 16323 megabytes. The VN device will round the size up to a machine page boundary. 164Filesystems up to 7.9 terabytes are supported. When specified along with 165a regular file, this option overrides the regular file's size insofar as 166VN is concerned. 167.It Fl T 168When a regular file is specified, VN will ftruncate() the file to 0 first. 169Normally you should also specify the 170.Fl S 171option to set the size of the file. 172This option also creates the file if it did not previously exist. 173This option is only meaningful if the 174.Fl S 175option has been specified. 176.It Fl Z 177When a regular file is specified, VN will zero the contents of the file to 178ensure that all blocks have been allocated by the filesystem. This option is 179only meaningful if the 180.Fl S 181option has been specified. 182.It Fl u 183Disable and ``unconfigure'' the device. 184.It Fl v 185Print messages to stdout describing actions taken. 186.El 187.Pp 188If no action option is given, 189.Fl c 190is assumed. 191.Pp 192The 193.Ar feature 194argument specifies a feature that can be enabled via the 195.Fl e 196option: 197.Bl -tag -width indent 198.It Dv swap 199Swapping is enabled on the special file. 200See 201.Xr swapon 2 . 202.It Dv mountro Ns = Ns Pa mount_point 203The special file is mounted read-only on 204.Ar mount_point . 205See 206.Xr mount 2 . 207.It Dv mountrw Ns = Ns Pa mount_point 208The special file is mounted read-write on 209.Ar mount_point . 210See 211.Xr mount 2 . 212.It Dv mount Ns = Ns Pa mount_point 213Same as ``mountrw=''. 214.El 215.Pp 216A configuration file contains one line per device/file pair in the form: 217.Bd -literal 218 special_file regular_file [ feature ] 219.Ed 220.Pp 221where fields are separated by white space. 222The previously described action options serve to configure, enable, 223disable or unconfigure all devices in the configuration file. 224.Sh FILES 225.Bl -tag -width /etc/vntab -compact 226.It Pa /etc/vntab 227default configuration file for 228.Fl a 229option 230.El 231.Sh EXAMPLES 232.Dl vnconfig vn0 /tmp/diskimage 233.Pp 234Configures the vnode disk 235.Pa vn0 . 236.Pp 237.Dl vnconfig -e vn0 /var/swapfile swap 238.Pp 239Configures 240.Pa vn0 241and enables swapping on it. 242.Pp 243.Dl vnconfig -c -v /dev/vn0 cdimage.iso 244.Dl mount -t cd9660 -o ro /dev/vn0 /mnt 245.Pp 246Mount an ISO9660 CD image file. 247.Pp 248.Dl umount /mnt 249.Dl vnconfig -u vn0 250.Pp 251Unmount the CD image file. 252.Pp 253.Dl vnconfig -d vn0 myfilesystem mount=/mnt 254.Pp 255Unmounts (disables) 256.Pa vn0 . 257.Pp 258.Dl vnconfig -ae 259.Pp 260Configures and enables all devices specified in 261.Pa /etc/vntab . 262.Pp 263.Dl vnconfig -s labels -c vn0 somebackingfile 264.Dl disklabel -r -w vn0s0 auto 265.Dl disklabel -e vn0s0 266.Pp 267Is an example of how to configure a file-backed VN disk with a disk label 268and to initialize and then edit the label. Once you create the label, you 269can partition your VN disk and, for example, create a filesystem on one of 270the partitions. If you are using a file as backing store, it may be possible 271to recover your VN disk after a crash by vnconfig'ing the same file again 272and using the VN configuration already stored in the file rather than 273relabeling and recreating the filesystem. It is even possible to fsck the 274VN partitions that previously contained filesystems. 275.Pp 276.Dl vnconfig -e -s labels,reserve -S 400m vn1 277.Dl disklabel -r -w vn1s0 auto 278.Dl newfs /dev/vn1s0 279.Dl mount /dev/vn1s0 /usr/obj 280.Pp 281Is an example of a swap-backed VN disk configuration. This example assumes 282that you have at least 400 megabytes of swap free (and hopefully much more). 283The swap space is pre-reserved in order to maintain maximum performance. 284We then label the disk, newfs it, and mount it as /usr/obj. Swap-backed VN 285devices are recoverable after a crash if you (A) use the reserve flag, and if 286(B) the same swap is reserved as was the last time, meaning that such 287vnconfig's would have to be run in your rc.local. In general, though, you 288only use swap-backed VN devices to hold information you don't mind losing 289on every reboot. 290.Sh SEE ALSO 291.Xr mount 2 , 292.Xr swapon 2 , 293.Xr unmount 2 , 294.Xr vn 4 295