OT: broken raid configuration persists too hard

[Emil Gorter]

On Mon, 14 Sep 2009 11:04:17 +0200,
Toni Mueller <support-fai at oeko.net> wrote:
>
> 
> 
> Hello,
> 
> I've noticed that, after unsuccessfully installing a machine via FAI, I
> was unable to undo the RAID configuration without resorting to extreme
> measures. Eg. popping in a regular Debian or Ubuntu CD, it was
> impossible to get rid of the pre-created RAID. Instead, the installer
> tried to force a RAID0, which I never configured (I only configure
> RAID1s), to be created.
> 
> The only measure I could find to eliminate this bogus RAID
> configuration, was to format all disks with BSD. Simply running dd
> if=/dev/zero of=/dev/sd[ab], under Linux, didn't yield the desired
> effect.

The raid-autodetect superblock is at the end of the disk.  You could dd 
zeroes over the end part, or simply:

	mdadm --zero-superblock /dev/sda

See man mdadm --metadata section about the superblock.

Emil Gorter

> 
> What gives?
> 
> TIA!
> 
> 
> Kind regards,
> --Toni++