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 December 31, 2000 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 56.Fl o 57.Oo Cm no Oc Ns Ar option 58.Oc 59.Op Fl s Ar size 60.Op Fl f Ar file 61.Op Fl S Ar sectorsize 62.Op Fl u Ar unit 63.Op Fl x Ar sectors/track 64.Op Fl y Ar heads/cyl 65.Nm 66.Fl d 67.Fl u Ar unit 68.Nm 69.Fl l 70.Op Fl n 71.Op Fl u Ar unit 72.Sh DESCRIPTION 73The 74.Nm 75utility configures and enables 76.Xr md 4 77devices. 78.Pp 79Options indicate an action to be performed: 80.Bl -tag -width indent 81.It Fl a 82Attach a memory disk. 83This will configure and attach a memory disk with the 84parameters specified and attach it to the system. 85.It Fl d 86Detach a memory disk from the system and release all resources. 87.It Fl t Ar type 88Select the type of the memory disk. 89.Bl -tag -width "preload" 90.It Cm malloc 91Storage for this type of memory disk is allocated with 92.Xr malloc 9 . 93This limits the size to the malloc bucket limit in the kernel. 94If the 95.Fl o Cm reserve 96option is not set, creating and filling a large 97malloc-backed memory disk is a very easy way to 98panic a system. 99.It Cm vnode 100A file specified with 101.Fl f Ar file 102becomes the backingstore for this memory disk. 103.It Cm swap 104swapspace is used to back this memory disk. 105.El 106.It Fl f Ar file 107Filename to use for the vnode type memory disk. 108.It Fl l 109List information about configured 110.Xr md 4 111devices. If the 112.Fl u 113option is used in conjuction with this, the output is limited to 114information on the specified device. 115.It Fl n 116When printing md device names, print only the unit number without the 117md prefix. 118.It Fl s Ar size 119Size of the memory disk. 120.Ar Size 121is the number of 512 byte sectors unless suffixed with a 122.Cm k , m , 123or 124.Cm g 125which 126denotes kilobyte, megabyte and gigabyte respectively. 127.It Fl S Ar sectorsize 128Sectorsize to use for malloc backed device. 129.It Fl x Ar sectors/track 130See description of 131.Fl y 132below. 133.It Fl y Ar heads/cylinder 134For malloc or vnode backed devices, the 135.Fl x 136and 137.Fl y 138options can be used to specify a synthetic geometry. 139This is useful for constructing bootable images for later download to 140other devices. 141.It Fl o Oo Cm no Oc Ns Ar option 142Set or reset options. 143.Bl -tag -width indent 144.It Oo Cm no Oc Ns Cm async 145For vnode backed devices: avoid IO_SYNC for increased performance but 146at the risk of deadlocking the entire kernel. 147.It Oo Cm no Oc Ns Cm reserve 148Allocate and reserve all needed storage from the start, rather than as needed. 149.It Oo Cm no Oc Ns Cm cluster 150Enable clustering on this disk. 151.It Oo Cm no Oc Ns Cm compress 152Enable/Disable compression features to reduce memory usage. 153.It Oo Cm no Oc Ns Cm force 154Disable/Enable extra sanity checks to prevent the user from doing something 155that might adversely affect the system. 156.It Oo Cm no Oc Ns Cm readonly 157Enable/Disable readonly mode. 158.El 159.It Fl u Ar unit 160Request a specific unit number for the 161.Xr md 4 162device instead of automatic allocation. 163.El 164.Sh EXAMPLES 165To create a 4 megabyte 166.Xr malloc 9 167backed memory disk. 168The name of the allocated unit will be output on stdout like 169.Dq Li md3 : 170.Pp 171.Dl mdconfig -a -t malloc -s 4m 172.Pp 173To create a disk named 174.Pa /dev/md4 175with 176.Pa /tmp/boot.flp 177as backing: 178.Pp 179.Dl mdconfig -a -t vnode -f /tmp/boot.flp -u 4 180.Pp 181To detach and free all resources used by 182.Pa /dev/md4 : 183.Pp 184.Dl mdconfig -d -u 4 185.Pp 186To create and mount a 128MByte swap backed file system on 187.Pa /tmp : 188.Bd -literal -offset indent 189mdconfig -a -t swap -s 128M -u 10 190newfs -U /dev/md10 191mount /dev/md10 /tmp 192chmod 1777 /tmp 193.Ed 194.Pp 195To create a 5MB file-backed disk: 196.Bd -literal -offset indent 197dd if=/dev/zero of=somebackingfile bs=1k count=5k 198mdconfig -a -t vnode -f somebackingfile -u 0 199bsdlabel -w md0 auto 200newfs md0c 201mount /dev/md0c /mnt 202.Ed 203.Sh SEE ALSO 204.Xr md 4 , 205.Xr bsdlabel 8 , 206.Xr fdisk 8 , 207.Xr mdmfs 8 , 208.Xr malloc 9 209.Sh HISTORY 210The 211.Nm 212utility first appeared in 213.Fx 5.0 214as a cleaner replacement for the 215.Xr vn 4 216and 217.Xr vnconfig 8 218combo. 219.Sh AUTHORS 220The 221.Nm 222utility was written by 223.An Poul-Henning Kamp 224.Aq phk@FreeBSD.org . 225