owl-users - Re: software raid with device busy status

Openwall GNU/*/Linux 3.0 - a small security-enhanced Linux distro for servers

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Date: Tue, 7 May 2013 16:29:25 +0200 (CEST)
From: Bernhard Fischer <fischerb@...cher-ing.de>
To: owl-users@...ts.openwall.com
Subject: Re: software raid with device busy status

Hi Misha,

you can't stop /dev/md0 if it's your root filesystem. It's like cutting
the branch you are sitting on.

If you remove a device from a raid set, you may also clear the
superblock for reusage.

mdadm --zero-superblock /dev/hda1

or do it the hard way

dd if=/dev/zero of=/dev/hda1

Check the other devices for proper bootloader installation. Otherwise
your machine will refuse booting afterwards. You have to install the
bootloader on every single device in the RAID set, to get it booting in
the case of a disaster.

-bernhard

Am Di 07.05.2013 15:45 schrieb misha shiposh <netsferato@...il.com>:

> Good day, guys!
> 
> I was wander, if there are any faq or guides of how to totally destroy
> raid
> array?
> 
> In my case I'll trying in a virtual sandbox to emulate this thing,
> without
> success...
> 
> After I create software raid 1, I'll try to delete it with the
> following
> steps:
> 
> Also this raid is root for my os,
> 
> first delete one of disk
> mdadm --manage /dev/md0 --fail /dev/hda1
> mdadm --manage /dev/md0 --remove /dev/hda1
> 
> then if I try to stop array md0 it says that it's busy.... no
> wonder...
> then I'll try to boot from removed disk and after that totally
> removing
> raid.
> 
> and no success!
> 
> stopping raid says it's busy, other way trying to delete the second
> disk
> without any result because of device is busy...
> 
> is there any way to totally destroy raid ?
> 
> 
> Thanks!