On Sun, 05 Jan 2014 10:07:50 +0100 Fabian Knorr <knorrfab@fim.uni-passau.de>
wrote:

> > Try this:
> > 
> > mdadm --stop /dev/md0
> > 
> > mdadm -Afv /dev/md0 /dev/sd[bcefghi]1
> > 
> > It leaves out /dev/sda, which appears to have been the spare in the
> > original setup.
> > 
> > If MD is happy after that, use fsck -n on your logical volumes to verify
> > your FS integrity, and/or see the extent of the damage (little or none,
> > I think).
> 
> This had the same result as simply trying --assemble --scan, see
> "assemble.log". I tried using sda1 instead of sdb1 as well as the both
> seem to have ID 4 ("assemble2.log"), same thing again.
> 
> Do you have any idea why mdadm seems to ignore --force and does not add
> the outdated disks? (Or am I misinterpreting --force?)

I haven't read the whole thread, but this sounds like the bug fixed by:

commit f81a2b56c4b437f66aaf5582a9c6b7f5ab2103c4
Author: NeilBrown <neilb@suse.de>
Date:   Tue Oct 22 09:55:04 2013 +1100

    Assembe: fix bug in force_array - it wasn't forcing properly.


try getting mdadm from git and building that
  git clone git://neil.brown.name/mdadm
  cd mdadm
  make

NeilBrown

> 
> Thanks.
> 
> Fabian