DragonFly On-Line Manual Pages

Search: Section:  

MDCP(1)                        Multi-Copy Device                       MDCP(1)


NAME

       mdcp - copy from a disk device to many.


SYNOPSIS

       mdcp <BS> <COUNT> <FILE_IN> <FILE_OUT_1>[ ... <FILE_OUT_N>]


DESCRIPTION

       Copy from device represented by FILE_IN to devices FILE_OUT_1,
       FILE_OUT_2, ..., FILE_OUT_N.

       BS     Block size. Leave it 0 to default size 32768.

       COUNT  Copy only COUNT blocks. Leave it 0 for copy until find EOF.

       FILE_IN
              Device to be read.

       FILE_OUT_N
              Nth device to be written.

       With mdcp, the data transfer rate is improved by making use of a much
       more efficient use of the transfer rate of the disks.

       The origin data is read only once, and is replicated in the destination
       devices. All working in parallel: all disks working at the same
       time,almost without interruption.

       Thus, the time to copy between devices falls considerably in relation
       to others existing utilities used to same propose - such as "dd".

       This system was developed aiming to reduce the time of the cloning of
       discs with pre-installed operating systems for multiple machines, but
       can be used for a big variety of porpouses.


EXAMPLES

       To copy from file "linux-hd1.img" to the devices hdb, hdc, and hdd:
              # mdcp 0 0 linux-hd1.img hdb hdc hdd

       To copy from device hda to hdb and hdc, first 1GB of data:
              # mdcp 32768 32768 /dev/hda /dev/hdb /dev/hdc

       Note that 32768 * 32768 = 1073741824 = 1GB

       To zero-fill the firsts 10GB from devices hdb, hdc and hdd you can do:
              # mdcp 0 327680 /dev/zero /dev/hdb /dev/hdc /dev/hdd

       Note that the name of the devices will can be change acordling to  wich
       OS you are.

       At FreeBSD OS, a copy would like as:
              # mdcp 0 0 myimg.img /dev/ad1 /dev/ad2 /dev/ad3


A COMPARATIVE ANALYSIS

       Copying 1 gigabyte (1,073,741,824 bytes) between IDE hard disks (UDMA
       133)

       UTILITY        FROM TO             TIME(secs)     Rate (b/s)
       dd             0:0  1:0            29             37,025,580
       dd             1:0  1:1            40             26,843,545

       mdcp           0:0  1:0            20             53,687,091
       mdcp           1:0  1:1            38             28,256,363

       mdcp           0:0  0:1, 1:0       32             67,108,864
       mdcp           0:0  1:0, 1:1       38             56,512,727

       mdcp           0:0  0:1, 1:0, 1:1  40             80,530,636

       Legend:
       0:0 = IDE 0 : Master
       0:1 = IDE 0 : Slave
       1:0 = IDE 1 : Master
       1:1 = IDE 1 : Slave

       Teste Details:
       Parameters passed to utilitys: block size = 32768, count = 32768
       System: Pentium 4, 1.8GHz, 512MB of RAM
       OS: FreeBSD 7


AUTHOR

       Wiritten by Wagner Monzyne. (MONZYNE, W.) <wamonzyne@hotmail.com>

BUGS and SUGESTIONS
       Please, send email to <wamonzyne@hotmail.com> to describe what you has
       experienced with this utility. Any questions or suggestions will be
       welcome.


COPYRIGHT

       Copyright (C) 2008 Wagner Monzyne (MONZYNE, W.)
       This is free software.  You may redistribute copies of it under the
       terms of the GNU General Public License
       <http://www.gnu.org/licenses/gpl.html>.  There is NO WARRANTY, to the
       extent permitted by law.

by Monzyne, W.                    April 2008                           MDCP(1)

Search: Section: