On Fri, 5 Mar 2010 12:05:32 -0800
Michael Evans [off-list ref] wrote:

Here's a stab at it. I've never tried to do it like this and haven't
glanced at the code so I can't be sure, but this seems to be the most
likely suspect:

#ARRAY /dev/md0 level=raid5 num-devices=4 devices=sda2,sdb2,sdd2,sdc2

Your commented out version seems to specify this mapping
0,sda2
1,sdb2
2,sdd2
3,sdc2

No it doesn't.  The 'devices=' lists is an unordered list (as set?).  It just
says "only try to include these devices in the array".  They still have to
have valid metadata, and it is the content of the metadata the defines the
role of the device in the array.

NeilBrown