Re: Disk cloning script...

From: Nancy Rudins (
Date: 04/10/05

Date: Sun, 10 Apr 2005 08:08:19 -0500

Stachu 'Dozzie' K. wrote:

> On 09.04.2005, Michael Pelletier <> wrote:
>> Stachu 'Dozzie' K. wrote:
>>> On 09.04.2005, Michael Pelletier <> wrote:
>>>> Hello,
>>>> I was wondering if anyone had, or knew of, a disk cloning script. I
>>>> need the script to make an exact copy of a system disk for backup
>>>> purposes.
>>> Hmm... `dd if=/dev/hda of=hda.dump' isn't sufficient?
>> Here is the situation. I have two disks let's say ad0 and ad1. How could
>> I use the dd command to mirror disk ad0 to disk ad1? I have a disk that I
>> think will go bad (acd0) and need to mirror it to a new disk (acd1)
>> before it dies...
> Quite simple. Let me assume that you're using some sort of
> FreeBSD Live CD[*] and want to mirror whole disk /dev/ad0 to /dev/ad1
> (ad1 has to be not smaller than ad0). Boot FreeBSD and start rescue
> shell, then type something like this:
> #v+
> dd if=/dev/ad0 of=/dev/ad1 bs=4096

Don't forget to include seek=1 skip=1 or you'll omit the block 0
bootstrap block. In other words, the command should be

dd if=/dev/ad0 of=/dev/ad1 bs=4096 seek=1 skip=1

When you're finished, it would help to fsck /dev/ad1

fskk /dev/rad1

Kind regards,

> #v-
> and wait until dd ends copying data. Then you can halt your machine,
> exchange disks on controller and you should be able to boot old system
> from the new disk.
> [*] Using Live CD here is not quite bad idea since you suspect that old
> disk is going to fail and want to minimize the old disk's use before
> finishing backup.

Flame War is over ... if you want it.
Nancy Rudins

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