[ltp] Re: Cloning a hard disk?

[Bret Comstock Waldow]

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On Fri, 19 Aug 2005 18:48, Jaime Iniesta wrote:
> It looks like my test didn't work. After 11 hours I aborted the process:
>
> root@0[dev]# dd if=3D/dev/hda of=3D/dev/uba bs=3D10M
> 1895+0 records in
> 1895+0 records out
> 19870515200 bytes transferred in 40062.003484 seconds (495994 bytes/sec)

On my T21, I used two identical disks, one mounted in the hard driver carri=
er=20
in the Ultrabay.  I booted on Tom's disk, and ran dd:

date; dd if=3D/dev/hda of=3D/dev/hdc bs=3D16384k; date

=46or 20 G disks, this took 2.8 hours.  Varying bs didn't change the time m=
uch.

On my T42, I use an external 2.5" USB2 drive case.  When I tried it the fir=
st=20
time, I used the stock 40G drive plus a 40G Seagate Momentus.  As the T42=20
doesn't have a floppy, and since I could leave the CDROM drive in, I booted=
=20
on the SystemRescue CD.

The first time I tried, it took 10 hours - not what I expected.

I discovered something odd, though, by accident.  If I boot the machine=20
normally, then unplug the external USB drive and replug it, it will duplica=
te=20
the drive in 50 minutes.  The command is:
dd if=3D/dev/hda of=3D/dev/sda bs=3D4096k

Disks are again identical (Seagate Momentus 80G now, though).

The version of dd on the SystemRescue CD and on my Gentoo install offer the=
=20
same number.

I presume the hotplugging causes it to pick up USB2 instead of USB1, and th=
at=20
explains the huge speed gain.  As I'm doing this from a running system (I l=
og=20
out of X and run as root) I run fsck -f on the ext3 linux partitions=20
afterwards, and fix some small errors usually.  I can then find my files on=
=20
the backup drive, and the partitions are correctly mirrored if I've changed=
=20
them.

I have switched drives and booted on the backup.  My Windows 98 partitions =
are=20
also successfully copied, and I've booted on that.

Neither in the T21, nor with the T42, have I been able to duplicate Windows=
=20
2000 or XP with this scheme.  In fact, the ORIGINAL copy will stop working=
=20
properly too!  It accepts my password, shows me the Royal Hourglass, and=20
returns me to the login dialog.

Happily, I have little need for Windows these days, and can run it in VMwar=
e=20
when  I do.

I don't remember if I've tried the hotplug trick with the SystemRescue CD, =
and=20
it's copy of dd.  I will tonight.

Cheers,
Bret

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