Re: How do I get rid of old device?

[Neil Brown <neilb@suse.de>]

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