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.\" Copyright (c) 2000 5.\" Poul-Henning Kamp All rights reserved. 6.\" 7.\" This code is derived from software contributed to Berkeley by 8.\" the Systems Programming Group of the University of Utah Computer 9.\" Science Department. 10.\" 11.\" Redistribution and use in source and binary forms, with or without 12.\" modification, are permitted provided that the following conditions 13.\" are met: 14.\" 1. Redistributions of source code must retain the above copyright 15.\" notice, this list of conditions and the following disclaimer. 16.\" 2. Redistributions in binary form must reproduce the above copyright 17.\" notice, this list of conditions and the following disclaimer in the 18.\" documentation and/or other materials provided with the distribution. 19.\" 3. All advertising materials mentioning features or use of this software 20.\" must display the following acknowledgement: 21.\" This product includes software developed by the University of 22.\" California, Berkeley and its contributors. 23.\" 4. Neither the name of the University nor the names of its contributors 24.\" may be used to endorse or promote products derived from this software 25.\" without specific prior written permission. 26.\" 27.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37.\" SUCH DAMAGE. 38.\" 39.\" @(#)vnconfig.8 8.1 (Berkeley) 6/5/93 40.\" from: src/usr.sbin/vnconfig/vnconfig.8,v 1.19 2000/12/27 15:30:29 41.\" 42.\" $FreeBSD$ 43.\" 44.Dd June 20, 2013 45.Dt MDCONFIG 8 46.Os 47.Sh NAME 48.Nm mdconfig 49.Nd configure and enable memory disks 50.Sh SYNOPSIS 51.Nm 52.Fl a 53.Fl t Ar type 54.Op Fl n 55.Oo Fl o Oo Cm no Oc Ns Ar option Oc ... 56.Op Fl f Ar file 57.Op Fl s Ar size 58.Op Fl S Ar sectorsize 59.Op Fl u Ar unit 60.Op Fl x Ar sectors/track 61.Op Fl y Ar heads/cylinder 62.Nm 63.Fl d 64.Fl u Ar unit 65.Op Fl o Oo Cm no Oc Ns Ar force 66.Nm 67.Fl r 68.Fl u Ar unit 69.Fl s Ar size 70.Op Fl o Oo Cm no Oc Ns Ar force 71.Nm 72.Fl l 73.Op Fl n 74.Op Fl v 75.Op Fl f Ar file 76.Op Fl u Ar unit 77.Nm 78.Ar file 79.Sh DESCRIPTION 80The 81.Nm 82utility configures and enables 83.Xr md 4 84devices. 85.Pp 86Options indicate an action to be performed: 87.Bl -tag -width indent 88.It Fl a 89Attach a memory disk. 90This will configure and attach a memory disk with the 91parameters specified and attach it to the system. 92.It Fl d 93Detach a memory disk from the system and release all resources. 94.It Fl r 95Resize a memory disk. 96.It Fl t Ar type 97Select the type of the memory disk. 98.Bl -tag -width "malloc" 99.It Cm malloc 100Storage for this type of memory disk is allocated with 101.Xr malloc 9 . 102This limits the size to the malloc bucket limit in the kernel. 103If the 104.Fl o Cm reserve 105option is not set, creating and filling a large 106malloc-backed memory disk is a very easy way to 107panic a system. 108.It Cm vnode 109A file specified with 110.Fl f Ar file 111becomes the backing store for this memory disk. 112.It Cm swap 113Storage for this type of memory disk is allocated from buffer 114memory. 115Pages get pushed out to swap when the system is under memory 116pressure, otherwise they stay in the operating memory. 117Using 118.Cm swap 119backing is generally preferred instead of using 120.Cm malloc 121backing. 122.El 123.It Fl f Ar file 124Filename to use for the vnode type memory disk. 125The 126.Fl a 127and 128.Fl t Ar vnode 129options are implied if not specified. 130.It Fl l 131List configured devices. 132If given with 133.Fl u , 134display details about that particular device. 135If given with 136.Fl f Ar file , 137display 138.Xr md 4 139device names of which 140.Ar file 141is used as the backing store. 142If both of 143.Fl u 144and 145.Fl f 146options are specified, 147display devices which match the two conditions. 148If the 149.Fl v 150option is specified, show all details. 151.It Fl n 152When printing 153.Xr md 4 154device names, print only the unit number without the 155.Xr md 4 156prefix. 157.It Fl s Ar size 158Size of the memory disk. 159.Ar Size 160is the number of 512 byte sectors unless suffixed with a 161.Cm b , k , m , g , 162or 163.Cm t 164which 165denotes byte, kilobyte, megabyte, gigabyte and terabyte respectively. 166The 167.Fl a 168and 169.Fl t Ar swap 170options are implied if not specified. 171.It Fl S Ar sectorsize 172Sectorsize to use for the memory disk, in bytes. 173.It Fl x Ar sectors/track 174See the description of the 175.Fl y 176option below. 177.It Fl y Ar heads/cylinder 178For 179.Cm malloc 180or 181.Cm vnode 182backed devices, the 183.Fl x 184and 185.Fl y 186options can be used to specify a synthetic geometry. 187This is useful for constructing bootable images for later download to 188other devices. 189.It Fl o Oo Cm no Oc Ns Ar option 190Set or reset options. 191.Bl -tag -width indent 192.It Oo Cm no Oc Ns Cm async 193For 194.Cm vnode 195backed devices: avoid 196.Dv IO_SYNC 197for increased performance but 198at the risk of deadlocking the entire kernel. 199.It Oo Cm no Oc Ns Cm reserve 200Allocate and reserve all needed storage from the start, rather than as needed. 201.It Oo Cm no Oc Ns Cm cluster 202Enable clustering on this disk. 203.It Oo Cm no Oc Ns Cm compress 204Enable/disable compression features to reduce memory usage. 205.It Oo Cm no Oc Ns Cm force 206Disable/enable extra sanity checks to prevent the user from doing something 207that might adversely affect the system. 208.It Oo Cm no Oc Ns Cm readonly 209Enable/disable readonly mode. 210.El 211.It Fl u Ar unit 212Request a specific unit number for the 213.Xr md 4 214device instead of automatic allocation. 215.El 216.Pp 217The last form, 218.Nm 219.Ar file , 220is provided for convenience as an abbreviation of 221.Nm 222.Fl a 223.Fl t Ar vnode 224.Fl f Ar file . 225.Sh EXAMPLES 226Create a 4 megabyte 227.Xr malloc 9 228backed memory disk. 229The name of the allocated unit will be printed on stdout, such as 230.Dq Li md3 : 231.Pp 232.Dl mdconfig -a -t malloc -s 4m 233.Pp 234Create a disk named 235.Pa /dev/md4 236with 237.Pa /tmp/boot.flp 238as backing storage: 239.Pp 240.Dl mdconfig -a -t vnode -f /tmp/boot.flp -u 4 241.Pp 242Detach and free all resources used by 243.Pa /dev/md4 : 244.Pp 245.Dl mdconfig -d -u 4 246.Pp 247Create a 128MByte swap backed disk, initialize an 248.Xr ffs 7 249file system on it, and mount it on 250.Pa /tmp : 251.Bd -literal -offset indent 252mdconfig -a -t swap -s 128M -u 10 253newfs -U /dev/md10 254mount /dev/md10 /tmp 255chmod 1777 /tmp 256.Ed 257.Pp 258Create a 5MB file-backed disk 259.Po Fl a 260and 261.Fl t Ar vnode 262are implied 263.Pc : 264.Bd -literal -offset indent 265dd if=/dev/zero of=somebackingfile bs=1k count=5k 266mdconfig -f somebackingfile -u 0 267bsdlabel -w md0 auto 268newfs md0c 269mount /dev/md0c /mnt 270.Ed 271.Pp 272Create an 273.Xr md 4 274device out of an ISO 9660 CD image file 275.Po Fl a 276and 277.Fl t Ar vnode 278are implied 279.Pc , using the first available 280.Xr md 4 281device, and then mount the new memory disk: 282.Bd -literal -offset indent 283mount -t cd9660 /dev/`mdconfig -f cdimage.iso` /mnt 284.Pp 285.Ed 286Create a file-backed device from a hard disk image that begins 287with 512K of raw header information. 288.Xr gnop 8 289is used to skip over the header information, positioning 290.Pa md1.nop 291to the start of the filesystem in the image. 292.Bd -literal -offset indent 293mdconfig -f diskimage.img -u 1 294gnop create -o 512K md1 295mount /dev/md1.nop /mnt 296.Ed 297.Sh SEE ALSO 298.Xr md 4 , 299.Xr ffs 7 , 300.Xr bsdlabel 8 , 301.Xr fdisk 8 , 302.Xr mdmfs 8 , 303.Xr malloc 9 304.Sh HISTORY 305The 306.Nm 307utility first appeared in 308.Fx 5.0 309as a cleaner replacement for the 310.Xr vn 4 311and 312.Xr vnconfig 8 313combo. 314.Sh AUTHORS 315The 316.Nm 317utility was written by 318.An Poul-Henning Kamp 319.Aq phk@FreeBSD.org . 320