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 1.7 2008/01/30 12:35:07 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 -S option. 80.Pp 81Options indicate an action to be performed: 82.Bl -tag -width indent 83.It Fl a 84Read a command file and performs the 85specified actions for each device/file pair. 86.It Fl c 87Configure the device. 88If successful, references to 89.Ar special_file 90will access the contents of 91.Ar regular_file . 92.It Fl d 93Disable (if possible) the specified feature. 94.It Fl e 95Configure the device and enables any 96.Ar feature 97that was specified. 98If no feature was specified, 99.Fl e 100is the same as 101.Fl c . 102.It Fl f Ar config_file 103Use 104.Ar config_file 105as an alternate config file. 106.It Fl g 107Fiddle global options. 108.It Fl l Ar special_file... 109List the vn devices and indicate which ones are in use. 110If a 111.Ar special_file 112list is given, only those devices will be described. 113.It Fl r Ar flag 114Reset 115.Ar flag . 116The list of allowed flags and their meanings are: 117.Bl -tag -width "follow" 118.It Ar labels 119use disk/slice labels. 120.It Ar reserve 121Pre-reserve the blocks underlying the file or swap backing store. Currently only 122works for swap backing store. This option also disables on-the-fly freeing of 123the underlying backing store (for example, when you remove a large file). 124Use this option if you wish to avoid long-term fragmentation of the backing 125store. Also note that when this option is used, the initial contents of the 126backing store may contain garbage rather than zeros. It may even be possible to 127recover the prior contents of a swap-backed VN across a reboot if the VN device 128is configured before any swap is allocated by the system. 129.It Ar follow 130debug flow in the 131.Xr vn 4 132driver. 133.It Ar debug 134debug data in the 135.Xr vn 4 136driver. 137.It Ar io 138debug I/O in the 139.Xr vn 4 140driver. 141.It Ar all 142turn on all flags. 143.It Ar none 144turn off all flags. 145.El 146.It Fl s Ar flag 147Set 148.Ar flag . 149The list of allowed flags and their meanings are the same as for the 150.Fl r 151option. 152.It Fl S Xo 153.Sm off 154.Ar value 155.Es \&{ \&} 156.En Cm k , m , g , t 157.Sm on 158.Xc 159If no regular file is specified, VN will use swap for backing store. 160This option specifies the size of the device. For example, '23m' for 16123 megabytes. The VN device will round the size up to a machine page boundary. 162Filesystems up to 7.9 terabytes are supported. When specified along with 163a regular file, this option overrides the regular file's size insofar as 164VN is concerned. 165.It Fl T 166When a regular file is specified, VN will ftruncate() the file to 0 first. 167Normally you should also specify the -S option to set the size of the file. 168This option also creates the file if it did not previously exist. 169This option is only meaningful if the -S option has been specified. 170.It Fl Z 171When a regular file is specified, VN will zero the contents of the file to 172ensure that all blocks have been allocated by the filesystem. This option is 173only meaningful if the -S option has been specified. 174.It Fl u 175Disable and ``unconfigure'' the device. 176.It Fl v 177Print messages to stdout describing actions taken. 178.El 179.Pp 180If no action option is given, 181.Fl c 182is assumed. 183.Pp 184The 185.Ar feature 186argument specifies a feature that can be enabled via the 187.Fl e 188option: 189.Bl -tag -width indent 190.It Dv swap 191Swapping is enabled on the special file. 192See 193.Xr swapon 2 . 194.It Dv mountro Ns = Ns Pa mount_point 195The special file is mounted read-only on 196.Ar mount_point . 197See 198.Xr mount 2 . 199.It Dv mountrw Ns = Ns Pa mount_point 200The special file is mounted read-write on 201.Ar mount_point . 202See 203.Xr mount 2 . 204.It Dv mount Ns = Ns Pa mount_point 205Same as ``mountrw=''. 206.El 207.Pp 208A configuration file contains one line per device/file pair in the form: 209.Bd -literal 210 special_file regular_file [ feature ] 211.Ed 212.Pp 213where fields are separated by white space. 214The previously described action options serve to configure, enable, 215disable or unconfigure all devices in the configuration file. 216.Sh FILES 217.Bl -tag -width /etc/vntab -compact 218.It Pa /etc/vntab 219default configuration file for 220.Fl a 221option 222.El 223.Sh EXAMPLES 224.Dl vnconfig vn0 /tmp/diskimage 225.Pp 226Configures the vnode disk 227.Pa vn0 . 228.Pp 229.Dl vnconfig -e vn0 /var/swapfile swap 230.Pp 231Configures 232.Pa vn0 233and enables swapping on it. 234.Pp 235.Dl vnconfig -c -v /dev/vn0 cdimage.iso 236.Dl mount -t cd9660 -o ro /dev/vn0 /mnt 237.Pp 238Mount an ISO9660 CD image file. 239.Pp 240.Dl umount /mnt 241.Dl vnconfig -u vn0 242.Pp 243Unmount the CD image file. 244.Pp 245.Dl vnconfig -d vn0 myfilesystem mount=/mnt 246.Pp 247Unmounts (disables) 248.Pa vn0 . 249.Pp 250.Dl vnconfig -ae 251.Pp 252Configures and enables all devices specified in 253.Pa /etc/vntab . 254.Pp 255.Dl vnconfig -s labels -c vn0 somebackingfile 256.Dl disklabel -r -w vn0s0 auto 257.Dl disklabel -e vn0s0 258.Pp 259Is an example of how to configure a file-backed VN disk with a disk label 260and to initialize and then edit the label. Once you create the label, you 261can partition your VN disk and, for example, create a filesystem on one of 262the partitions. If you are using a file as backing store, it may be possible 263to recover your VN disk after a crash by vnconfig'ing the same file again 264and using the VN configuration already stored in the file rather than 265relabeling and recreating the filesystem. It is even possible to fsck the 266VN partitions that previously contained filesystems. 267.Pp 268.Dl vnconfig -e -s labels,reserve -S 400m vn1 269.Dl disklabel -r -w vn1s0 auto 270.Dl newfs /dev/vn1s0 271.Dl mount /dev/vn1s0 /usr/obj 272.Pp 273Is an example of a swap-backed VN disk configuration. This example assumes 274that you have at least 400 megabytes of swap free (and hopefully much more). 275The swap space is pre-reserved in order to maintain maximum performance. 276We then label the disk, newfs it, and mount it as /usr/obj. Swap-backed VN 277devices are recoverable after a crash if you (A) use the reserve flag, and if 278(B) the same swap is reserved as was the last time, meaning that such 279vnconfig's would have to be run in your rc.local. In general, though, you 280only use swap-backed VN devices to hold information you don't mind losing 281on every reboot. 282.Sh SEE ALSO 283.Xr mount 2 , 284.Xr swapon 2 , 285.Xr unmount 2 , 286.Xr vn 4 287