On Wed, 11 Aug 2010 09:04:32 +0200
Tobias Gunkel [off-list ref] wrote:

Hello everyone,

I've got a strange SparesMissing event on one of my raid1 arrays.
mdadm --detail /dev/md2 says all ok, but I get this message by mdadm
monitor every day:

A SparesMissing event had been detected on md device /dev/md2.

This means that /etc/mdadm/mdadm.conf says /dev/md2 has more spare devices
than it currently has.  What is in /etc/mdadm/mdadm.conf

This makes me wonder, too:

root@MCI03:~# mdadm --examine --scan
ARRAY /dev/md0 UUID=304f5f2a:fbc8082b:54307b3d:1949437b
   spares=1
ARRAY /dev/md1 UUID=b263f9c1:5c680152:54307b3d:1949437b
   spares=1
ARRAY /dev/md2 UUID=7aa24776:9d6e8d24:54307b3d:1949437b
   spares=2

Why spares=2 for md2? It was created during Debian system install with
spares=1.

What do you get if you run

 mdadm --examine --scan --verbose

it should add a 'devices=' line which will show you which devices it is
counting.

NeilBrown