On Thu, 17 Jan 2008, Neil Brown wrote:

On Wednesday January 16, jpiszcz@lucidpixels.com wrote:

quoted

p34:~# mdadm /dev/md3 --zero-superblock
p34:~# mdadm --examine --scan
ARRAY /dev/md0 level=raid1 num-devices=2
UUID=f463057c:9a696419:3bcb794a:7aaa12b2
ARRAY /dev/md1 level=raid1 num-devices=2
UUID=98e4948c:c6685f82:e082fd95:e7f45529
ARRAY /dev/md2 level=raid1 num-devices=2
UUID=330c9879:73af7d3e:57f4c139:f9191788
ARRAY /dev/md3 level=raid0 num-devices=10
UUID=6dc12c36:b3517ff9:083fb634:68e9eb49
p34:~#

I cannot seem to get rid of /dev/md3, its almost as if there is a piece of
it on the root (2) disks or reference to it?

I also dd'd the other 10 disks (non-root) and /dev/md3 persists.

You don't zero the superblock on the array device, because the array
device does not have a superblock.  The component devices have the
superblock.

So
 mdadm --zero-superblock /dev/sd*
or whatever.
Maybe
 mdadm --examine --scan -v

then get the list of devices it found for the array you want to kill,
and  --zero-superblock that list.

NeilBrown

Thanks, will keep this in mind for the future-- I just checked and the 
dd's have finished and there is no longer a /dev/md3, but mdadm 
--zero-superblock /dev/sd[c-l] would have been much easier.

Justin.