Re: Yet another RAID admin question

[Hendrik Boom <hendrik@topoi.pooq.com>]

On Tue, 17 Feb 2009 18:22:43 +0100, martin f krafft wrote:

> also sprach Hendrik Boom <hendrik@topoi.pooq.com> [2009.02.17.1747
> +0100]:
>> But I understand these partitions are marked in some way to identify
>> them as RAID members, and that these marks are used at boot time to
>> asssemble the RAID.
>> 
>> What do I have to do to make sure that after I have removed the old
>> member it is never again recognised as a RAID member?
> 
> There's a superblock. When mdadm starts, it scans the devices listed for
> DEVICES in mdadm.conf (or all partitions if it says 'partitions') for
> superblocks.
> 
> You can remove a superblock with --zero-superblock. See mdadm(8).

So the procedure would be somehtinglike:

   mdadm --fail /dev/md0 /dev/hda3
to stop it from using /dev/hda3.  After this it should spend a happy hour 
copying the data on /dev/sda3, the other active drive to /dev/sdb3. the 
current spare.

   mdadm --remove /dev/md0 /dev/hda3
to remove it from the set, and 

   mdadm --zero-superblock /dev/hda3
to make sure it never comes back.  Presumably I'm not supposed to 
mention /dev/md0 on this command because /dev/hda3 is no longer part of 
it.

-- hendrik