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Man Pages


Manual Reference Pages  -  MDCP (1)

NAME

mdcp - copy from a disk device to many.

CONTENTS

Synopsis
Description
Examples
A Comparative Analysis
Author
BUGS and SUGESTIONS
Copyright

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 © 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.

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by Monzyne, W. MDCP (1) April 2008

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