IPB
>  Man Pages > Unix > FreeBSD 6.2 > Section 8 > mdconfig man page

mdconfig man page

Section 8 - FreeBSD 6.2 Man Pages

Other operating system man pages available here


Advanced Search

Hopefully, this page is exactly what you are looking for, but if not, you can always find further assistance on Unix/Linux Forum!


MDCONFIG(8)             FreeBSD System Manager's Manual            MDCONFIG(8)


NAME

     mdconfig -- configure and enable memory disks


SYNOPSIS

     mdconfig -a -t type [-n] [-o [no]option] ... [-f file] [-s size]
              [-S sectorsize] [-u unit] [-x sectors/track] [-y heads/cyl]
     mdconfig -d -u unit
     mdconfig -l [-n] [-u unit]


DESCRIPTION

     The mdconfig utility configures and enables md(4) devices.

     Options indicate an action to be performed:

     -a      Attach a memory disk.  This will configure and attach a memory
             disk with the parameters specified and attach it to the system.

     -d      Detach a memory disk from the system and release all resources.

     -t type
             Select the type of the memory disk.

             malloc   Storage for this type of memory disk is allocated with
                      malloc(9).  This limits the size to the malloc bucket
                      limit in the kernel.  If the -o reserve option is not
                      set, creating and filling a large malloc-backed memory
                      disk is a very easy way to panic a system.

             vnode    A file specified with -f file becomes the backingstore
                      for this memory disk.

             swap     Swap space is used to back this memory disk.

     -f file
             Filename to use for the vnode type memory disk.

     -l      List configured devices.  If given with -u, display details about
             that particular device.

     -n      When printing md device names, print only the unit number without
             the md prefix.

     -s size
             Size of the memory disk.  Size is the number of 512 byte sectors
             unless suffixed with a b, k, m, g, or t which denotes byte, kilo-
             byte, megabyte, gigabyte and terabyte respectively.

     -S sectorsize
             Sectorsize to use for malloc backed device.

     -x sectors/track
             See the description of the -y option below.

     -y heads/cylinder
             For malloc or vnode backed devices, the -x and -y options can be
             used to specify a synthetic geometry.  This is useful for con-
             structing bootable images for later download to other devices.

     -o [no]option
             Set or reset options.

             [no]async
                     For vnode backed devices: avoid IO_SYNC for increased
                     performance but at the risk of deadlocking the entire
                     kernel.

             [no]reserve
                     Allocate and reserve all needed storage from the start,
                     rather than as needed.

             [no]cluster
                     Enable clustering on this disk.

             [no]compress
                     Enable/Disable compression features to reduce memory
                     usage.

             [no]force
                     Disable/Enable extra sanity checks to prevent the user
                     from doing something that might adversely affect the sys-
                     tem.

             [no]readonly
                     Enable/Disable readonly mode.

     -u unit
             Request a specific unit number for the md(4) device instead of
             automatic allocation.


EXAMPLES

     To create a 4 megabyte malloc(9) backed memory disk.  The name of the
     allocated unit will be output on stdout like ``md3'':

           mdconfig -a -t malloc -s 4m

     To create a disk named /dev/md4 with /tmp/boot.flp as backing:

           mdconfig -a -t vnode -f /tmp/boot.flp -u 4

     To detach and free all resources used by /dev/md4:

           mdconfig -d -u 4

     To create and mount a 128MByte swap backed file system on /tmp:

           mdconfig -a -t swap -s 128M -u 10
           newfs -U /dev/md10
           mount /dev/md10 /tmp
           chmod 1777 /tmp

     To create a 5MB file-backed disk:

           dd if=/dev/zero of=somebackingfile bs=1k count=5k
           mdconfig -a -t vnode -f somebackingfile -u 0
           bsdlabel -w md0 auto
           newfs md0c
           mount /dev/md0c /mnt


SEE ALSO

     md(4), bsdlabel(8), fdisk(8), mdmfs(8), malloc(9)


HISTORY

     The mdconfig utility first appeared in FreeBSD 5.0 as a cleaner replace-
     ment for the vn(4) and vnconfig(8) combo.


AUTHORS

     The mdconfig utility was written by Poul-Henning Kamp <phk@FreeBSD.org>.

FreeBSD 6.2                    November 6, 2004                    FreeBSD 6.2


Man(1) output converted with man2html and wrapped by fishsponge

This page was generated on Wed Sep 19 20:35:21 BST 2007

Your favourite pages:

No pages logged yet.
Trying to save cookie...

Top 10 most popular pages:

sqlite3 man page (5333 hits)
(openSUSE 10.2)

svn man page (5208 hits)
(FreeBSD 6.2)

adv_cap_autoneg man page (4870 hits)
(Solaris 10 11_06)

CPAN man page (4607 hits)
(Suse Linux 10.1)

ssh man page (4342 hits)
(Suse Linux 10.1)

ssh-socks5-proxy-connect man page (2874 hits)
(Solaris 10 11_06)

netcat man page (2717 hits)
(Suse Linux 10.1)

pprosetup man page (2487 hits)
(Solaris 10 11_06)

startproc man page (2471 hits)
(Suse Linux 10.1)

signal man page (2406 hits)
(Suse Linux 10.1)

Useful Links

Go Back

Visitor Statistics


Valid XHTML 1.0 Transitional     Valid CSS!

Partners: Cambridge Plus :: Pyrenees Travel :: Electronic Consultancy, UK :: <Link Available>
Unix Man Pages / Linux Man Pages :: HiFi Forum :: SIP VoIP Phone & Provider Reviews :: UNIX/Linux Forum Archives

More info on advertising on Unix/Linux Forum