mdcp man page on DragonFly
[printable version]
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 © 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)
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