Re: Deleting mdadm RAID arrays

[Marcin Krol <admin@domeny.pl>]

Tuesday 05 February 2008 21:12:32 Neil Brown napisał(a):

> > % mdadm --zero-superblock /dev/sdb1
> > mdadm: Couldn't open /dev/sdb1 for write - not zeroing
> 
> That's weird.
> Why can't it open it?

Hell if I know. First time I see such a thing. 

> Maybe you aren't running as root (The '%' prompt is suspicious).

I am running as root, the "%" prompt is the obfuscation part (I have
configured bash to display IP as part of prompt).

> Maybe the kernel has  been told to forget about the partitions of
> /dev/sdb.

But fdisk/cfdisk has no problem whatsoever finding the partitions .

> mdadm will sometimes tell it to do that, but only if you try to
> assemble arrays out of whole components.

> If that is the problem, then
>    blockdev --rereadpt /dev/sdb

I deleted LVM devices that were sitting on top of RAID and reinstalled mdadm.

% blockdev --rereadpt /dev/sdf
BLKRRPART: Device or resource busy

% mdadm /dev/md2 --fail /dev/sdf1
mdadm: set /dev/sdf1 faulty in /dev/md2

% blockdev --rereadpt /dev/sdf
BLKRRPART: Device or resource busy

% mdadm /dev/md2 --remove /dev/sdf1
mdadm: hot remove failed for /dev/sdf1: Device or resource busy

lsof /dev/sdf1 gives ZERO results.

arrrRRRGH

Regards,
Marcin Krol
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