| 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. |
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| 10 | .\" modification, are permitted provided that the following conditions |
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| 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 |
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| 25 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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| 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 1.5 2007/08/10 18:28:27 swildner Exp $ |
| 40 | .\" |
| 41 | .Dd July 8, 1993 |
| 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 | .Sh DESCRIPTION |
| 64 | The |
| 65 | .Nm |
| 66 | command configures and enables vnode pseudo disk devices. |
| 67 | The first form of the command will associate the special file |
| 68 | .Ar special_file |
| 69 | with the regular file |
| 70 | .Ar regular_file |
| 71 | allowing the latter to be accessed as though it were a disk. |
| 72 | Hence a regular file within the filesystem can be used for swapping |
| 73 | or can contain a filesystem that is mounted in the name space. If you |
| 74 | want to use swap backing store for your device instead of a file, you |
| 75 | can leave regular_file out and specify the size of the block device |
| 76 | with the -S option. |
| 77 | .Pp |
| 78 | Options indicate an action to be performed: |
| 79 | .Bl -tag -width indent |
| 80 | .It Fl a |
| 81 | Read a command file and performs the |
| 82 | specified actions for each device/file pair. |
| 83 | .It Fl c |
| 84 | Configure the device. |
| 85 | If successful, references to |
| 86 | .Ar special_file |
| 87 | will access the contents of |
| 88 | .Ar regular_file . |
| 89 | .It Fl d |
| 90 | Disable (if possible) the specified feature. |
| 91 | .It Fl e |
| 92 | Configure the device and enables any |
| 93 | .Ar feature |
| 94 | that was specified. |
| 95 | If no feature was specified, |
| 96 | .Fl e |
| 97 | is the same as |
| 98 | .Fl c . |
| 99 | .It Fl f Ar config_file |
| 100 | Use |
| 101 | .Ar config_file |
| 102 | as an alternate config file. |
| 103 | .It Fl g |
| 104 | Fiddle global options. |
| 105 | .It Fl r Ar flag |
| 106 | Reset |
| 107 | .Ar flag . |
| 108 | The list of allowed flags and their meanings are: |
| 109 | .Bl -tag -width "follow" |
| 110 | .It Ar labels |
| 111 | use disk/slice labels. |
| 112 | .It Ar reserve |
| 113 | Pre-reserve the blocks underlying the file or swap backing store. Currently only |
| 114 | works for swap backing store. This option also disables on-the-fly freeing of |
| 115 | the underlying backing store (for example, when you remove a large file). |
| 116 | Use this option if you wish to avoid long-term fragmentation of the backing |
| 117 | store. Also note that when this option is used, the initial contents of the |
| 118 | backing store may contain garbage rather than zeros. It may even be possible to |
| 119 | recover the prior contents of a swap-backed VN across a reboot if the VN device |
| 120 | is configured before any swap is allocated by the system. |
| 121 | .It Ar follow |
| 122 | debug flow in the |
| 123 | .Xr vn 4 |
| 124 | driver. |
| 125 | .It Ar debug |
| 126 | debug data in the |
| 127 | .Xr vn 4 |
| 128 | driver. |
| 129 | .It Ar io |
| 130 | debug I/O in the |
| 131 | .Xr vn 4 |
| 132 | driver. |
| 133 | .It Ar all |
| 134 | turn on all flags. |
| 135 | .It Ar none |
| 136 | turn off all flags. |
| 137 | .El |
| 138 | .It Fl s Ar flag |
| 139 | Set |
| 140 | .Ar flag . |
| 141 | The list of allowed flags and their meanings are the same as for the |
| 142 | .Fl r |
| 143 | option. |
| 144 | .It Fl S Xo |
| 145 | .Sm off |
| 146 | .Ar value |
| 147 | .Es \&{ \&} |
| 148 | .En Cm k , m , g , t |
| 149 | .Sm on |
| 150 | .Xc |
| 151 | If no regular file is specified, VN will use swap for backing store. |
| 152 | This option specifies the size of the device. For example, '23m' for |
| 153 | 23 megabytes. The VN device will round the size up to a machine page boundary. |
| 154 | Filesystems up to 7.9 terabytes are supported. When specified along with |
| 155 | a regular file, this option overrides the regular file's size insofar as |
| 156 | VN is concerned. |
| 157 | .It Fl T |
| 158 | When a regular file is specified, VN will ftruncate() the file to 0 first. |
| 159 | Normally you should also specify the -S option to set the size of the file. |
| 160 | This option also creates the file if it did not previously exist. |
| 161 | This option is only meaningful if the -S option has been specified. |
| 162 | .It Fl Z |
| 163 | When a regular file is specified, VN will zero the contents of the file to |
| 164 | ensure that all blocks have been allocated by the filesystem. This option is |
| 165 | only meaningful if the -S option has been specified. |
| 166 | .It Fl u |
| 167 | Disable and ``unconfigure'' the device. |
| 168 | .It Fl v |
| 169 | Print messages to stdout describing actions taken. |
| 170 | .El |
| 171 | .Pp |
| 172 | If no action option is given, |
| 173 | .Fl c |
| 174 | is assumed. |
| 175 | .Pp |
| 176 | The |
| 177 | .Ar feature |
| 178 | argument specifies a feature that can be enabled via the |
| 179 | .Fl e |
| 180 | option: |
| 181 | .Bl -tag -width indent |
| 182 | .It Dv swap |
| 183 | Swapping is enabled on the special file. |
| 184 | See |
| 185 | .Xr swapon 2 . |
| 186 | .It Dv mountro Ns = Ns Pa mount_point |
| 187 | The special file is mounted read-only on |
| 188 | .Ar mount_point . |
| 189 | See |
| 190 | .Xr mount 2 . |
| 191 | .It Dv mountrw Ns = Ns Pa mount_point |
| 192 | The special file is mounted read-write on |
| 193 | .Ar mount_point . |
| 194 | See |
| 195 | .Xr mount 2 . |
| 196 | .It Dv mount Ns = Ns Pa mount_point |
| 197 | Same as ``mountrw=''. |
| 198 | .El |
| 199 | .Pp |
| 200 | A configuration file contains one line per device/file pair in the form: |
| 201 | .Bd -literal |
| 202 | special_file regular_file [ feature ] |
| 203 | .Ed |
| 204 | .Pp |
| 205 | where fields are separated by white space. |
| 206 | The previously described action options serve to configure, enable, |
| 207 | disable or unconfigure all devices in the configuration file. |
| 208 | .Sh FILES |
| 209 | .Bl -tag -width /etc/vntab -compact |
| 210 | .It Pa /etc/vntab |
| 211 | default configuration file for |
| 212 | .Fl a |
| 213 | option |
| 214 | .El |
| 215 | .Sh EXAMPLES |
| 216 | .Dl vnconfig vn0 /tmp/diskimage |
| 217 | .Pp |
| 218 | Configures the vnode disk |
| 219 | .Pa vn0 . |
| 220 | .Pp |
| 221 | .Dl vnconfig -e vn0 /var/swapfile swap |
| 222 | .Pp |
| 223 | Configures |
| 224 | .Pa vn0 |
| 225 | and enables swapping on it. |
| 226 | .Pp |
| 227 | .Dl vnconfig -c -v /dev/vn0 cdimage.iso |
| 228 | .Dl mount -t cd9660 -o ro /dev/vn0 /mnt |
| 229 | .Pp |
| 230 | Mount an ISO9660 CD image file. |
| 231 | .Pp |
| 232 | .Dl umount /mnt |
| 233 | .Dl vnconfig -u vn0 |
| 234 | .Pp |
| 235 | Unmount the CD image file. |
| 236 | .Pp |
| 237 | .Dl vnconfig -d vn0 myfilesystem mount=/mnt |
| 238 | .Pp |
| 239 | Unmounts (disables) |
| 240 | .Pa vn0 . |
| 241 | .Pp |
| 242 | .Dl vnconfig -ae |
| 243 | .Pp |
| 244 | Configures and enables all devices specified in |
| 245 | .Pa /etc/vntab . |
| 246 | .Pp |
| 247 | .Dl vnconfig -s labels -c vn0 somebackingfile |
| 248 | .Dl disklabel -r -w vn0s0 auto |
| 249 | .Dl disklabel -e vn0s0 |
| 250 | .Pp |
| 251 | Is an example of how to configure a file-backed VN disk with a disk label |
| 252 | and to initialize and then edit the label. Once you create the label, you |
| 253 | can partition your VN disk and, for example, create a filesystem on one of |
| 254 | the partitions. If you are using a file as backing store, it may be possible |
| 255 | to recover your VN disk after a crash by vnconfig'ing the same file again |
| 256 | and using the VN configuration already stored in the file rather than |
| 257 | relabeling and recreating the filesystem. It is even possible to fsck the |
| 258 | VN partitions that previously contained filesystems. |
| 259 | .Pp |
| 260 | .Dl vnconfig -e -s labels,reserve -S 400m vn1 |
| 261 | .Dl disklabel -r -w vn1s0 auto |
| 262 | .Dl newfs /dev/vn1s0 |
| 263 | .Dl mount /dev/vn1s0 /usr/obj |
| 264 | .Pp |
| 265 | Is an example of a swap-backed VN disk configuration. This example assumes |
| 266 | that you have at least 400 megabytes of swap free (and hopefully much more). |
| 267 | The swap space is pre-reserved in order to maintain maximum performance. |
| 268 | We then label the disk, newfs it, and mount it as /usr/obj. Swap-backed VN |
| 269 | devices are recoverable after a crash if you (A) use the reserve flag, and if |
| 270 | (B) the same swap is reserved as was the last time, meaning that such |
| 271 | vnconfig's would have to be run in your rc.local. In general, though, you |
| 272 | only use swap-backed VN devices to hold information you don't mind losing |
| 273 | on every reboot. |
| 274 | .Sh SEE ALSO |
| 275 | .Xr mount 2 , |
| 276 | .Xr swapon 2 , |
| 277 | .Xr unmount 2 , |
| 278 | .Xr vn 4 |