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 November 28, 2007 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/cyl 62.Nm 63.Fl d 64.Fl u Ar unit 65.Nm 66.Fl l 67.Op Fl n 68.Op Fl u Ar unit 69.Sh DESCRIPTION 70The 71.Nm 72utility configures and enables 73.Xr md 4 74devices. 75.Pp 76Options indicate an action to be performed: 77.Bl -tag -width indent 78.It Fl a 79Attach a memory disk. 80This will configure and attach a memory disk with the 81parameters specified and attach it to the system. 82.It Fl d 83Detach a memory disk from the system and release all resources. 84.It Fl t Ar type 85Select the type of the memory disk. 86.Bl -tag -width "preload" 87.It Cm malloc 88Storage for this type of memory disk is allocated with 89.Xr malloc 9 . 90This limits the size to the malloc bucket limit in the kernel. 91If the 92.Fl o Cm reserve 93option is not set, creating and filling a large 94malloc-backed memory disk is a very easy way to 95panic a system. 96.It Cm vnode 97A file specified with 98.Fl f Ar file 99becomes the backing store for this memory disk. 100.It Cm swap 101Storage for this type of memory disk is allocated from buffer 102memory. 103Pages get pushed out to the swap when the system is under memory 104pressure, otherwise they stay in the operating memory. 105Using 106.Cm swap 107backing is generally preferable over 108.Cm malloc 109backing. 110.El 111.It Fl f Ar file 112Filename to use for the vnode type memory disk. Options 113.Fl a 114and 115.Fl t Ar vnode 116are implied if not specified. 117.It Fl l 118List configured devices. 119If given with 120.Fl u , 121display details about that particular device. 122.It Fl n 123When printing md device names, print only the unit number without the 124md prefix. 125.It Fl s Ar size 126Size of the memory disk. 127.Ar Size 128is the number of 512 byte sectors unless suffixed with a 129.Cm b , k , m , g , 130or 131.Cm t 132which 133denotes byte, kilobyte, megabyte, gigabyte and terabyte respectively. Options 134.Fl a 135and 136.Fl t Ar swap 137are implied if not specified. 138.It Fl S Ar sectorsize 139Sectorsize to use for malloc backed device. 140.It Fl x Ar sectors/track 141See the description of the 142.Fl y 143option below. 144.It Fl y Ar heads/cylinder 145For 146.Cm malloc 147or 148.Cm vnode 149backed devices, the 150.Fl x 151and 152.Fl y 153options can be used to specify a synthetic geometry. 154This is useful for constructing bootable images for later download to 155other devices. 156.It Fl o Oo Cm no Oc Ns Ar option 157Set or reset options. 158.Bl -tag -width indent 159.It Oo Cm no Oc Ns Cm async 160For 161.Cm vnode 162backed devices: avoid 163.Dv IO_SYNC 164for increased performance but 165at the risk of deadlocking the entire kernel. 166.It Oo Cm no Oc Ns Cm reserve 167Allocate and reserve all needed storage from the start, rather than as needed. 168.It Oo Cm no Oc Ns Cm cluster 169Enable clustering on this disk. 170.It Oo Cm no Oc Ns Cm compress 171Enable/Disable compression features to reduce memory usage. 172.It Oo Cm no Oc Ns Cm force 173Disable/Enable extra sanity checks to prevent the user from doing something 174that might adversely affect the system. 175.It Oo Cm no Oc Ns Cm readonly 176Enable/Disable readonly mode. 177.El 178.It Fl u Ar unit 179Request a specific unit number for the 180.Xr md 4 181device instead of automatic allocation. 182.El 183.Sh EXAMPLES 184To create a 4 megabyte 185.Xr malloc 9 186backed memory disk. 187The name of the allocated unit will be output on stdout like 188.Dq Li md3 : 189.Pp 190.Dl mdconfig -a -t malloc -s 4m 191.Pp 192To create a disk named 193.Pa /dev/md4 194with 195.Pa /tmp/boot.flp 196as backing storage: 197.Pp 198.Dl mdconfig -a -t vnode -f /tmp/boot.flp -u 4 199.Pp 200To detach and free all resources used by 201.Pa /dev/md4 : 202.Pp 203.Dl mdconfig -d -u 4 204.Pp 205To create a 128MByte swap backed disk, initialize an 206.Xr ffs 7 207file system on it, and mount it on 208.Pa /tmp : 209.Bd -literal -offset indent 210mdconfig -a -t swap -s 128M -u 10 211newfs -U /dev/md10 212mount /dev/md10 /tmp 213chmod 1777 /tmp 214.Ed 215.Pp 216To create a 5MB file-backed disk 217.Ns ( Fl a 218and 219.Fl t Ar vnode 220are implied): 221.Bd -literal -offset indent 222dd if=/dev/zero of=somebackingfile bs=1k count=5k 223mdconfig -f somebackingfile -u 0 224bsdlabel -w md0 auto 225newfs md0c 226mount /dev/md0c /mnt 227.Ed 228.Pp 229To create an 230.Xr md 4 231device out of an ISO 9660 CD image file 232.Ns ( Fl a 233and 234.Fl t Ar vnode 235are implied), using the first available 236.Xr md 4 237device, and then mount the new memory disk: 238.Bd -literal -offset indent 239mount -t cd9660 /dev/`mdconfig -f cdimage.iso` /mnt 240.Ed 241.Sh SEE ALSO 242.Xr md 4 , 243.Xr ffs 7 , 244.Xr bsdlabel 8 , 245.Xr fdisk 8 , 246.Xr mdmfs 8 , 247.Xr malloc 9 248.Sh HISTORY 249The 250.Nm 251utility first appeared in 252.Fx 5.0 253as a cleaner replacement for the 254.Xr vn 4 255and 256.Xr vnconfig 8 257combo. 258.Sh AUTHORS 259The 260.Nm 261utility was written by 262.An Poul-Henning Kamp 263.Aq phk@FreeBSD.org . 264