Hi Florian,

On 02/15/2014 01:52 PM, Florian Lampel wrote:

Well, that did not went as well as I had hoped. Here is what happened:

root@Lserve:~# mdadm --stop /dev/md0
mdadm: stopped /dev/md0
root@Lserve:~# mdadm -Afv /dev/md0 /dev/sd[abcefghjklm]1
mdadm: looking for devices for /dev/md0
mdadm: /dev/sda1 is identified as a member of /dev/md0, slot 4.
mdadm: /dev/sdb1 is identified as a member of /dev/md0, slot 5.
mdadm: /dev/sdc1 is identified as a member of /dev/md0, slot 6.
mdadm: /dev/sde1 is identified as a member of /dev/md0, slot 8.
mdadm: /dev/sdf1 is identified as a member of /dev/md0, slot 9.
mdadm: /dev/sdg1 is identified as a member of /dev/md0, slot 10.
mdadm: /dev/sdh1 is identified as a member of /dev/md0, slot 11.
mdadm: /dev/sdj1 is identified as a member of /dev/md0, slot 0.
mdadm: /dev/sdk1 is identified as a member of /dev/md0, slot 1.
mdadm: /dev/sdl1 is identified as a member of /dev/md0, slot 2.
mdadm: /dev/sdm1 is identified as a member of /dev/md0, slot 3.
mdadm: forcing event count in /dev/sde1(8) from 435 upto 442
mdadm: forcing event count in /dev/sdf1(9) from 435 upto 442
mdadm: forcing event count in /dev/sdg1(10) from 435 upto 442
mdadm: forcing event count in /dev/sdh1(11) from 435 upto 442
mdadm: clearing FAULTY flag for device 3 in /dev/md0 for /dev/sde1
mdadm: clearing FAULTY flag for device 4 in /dev/md0 for /dev/sdf1
mdadm: clearing FAULTY flag for device 5 in /dev/md0 for /dev/sdg1
mdadm: clearing FAULTY flag for device 6 in /dev/md0 for /dev/sdh1
mdadm: Marking array /dev/md0 as 'clean'
mdadm: added /dev/sdk1 to /dev/md0 as 1
mdadm: added /dev/sdl1 to /dev/md0 as 2
mdadm: added /dev/sdm1 to /dev/md0 as 3
mdadm: added /dev/sda1 to /dev/md0 as 4
mdadm: added /dev/sdb1 to /dev/md0 as 5
mdadm: added /dev/sdc1 to /dev/md0 as 6
mdadm: no uptodate device for slot 7 of /dev/md0
mdadm: added /dev/sde1 to /dev/md0 as 8
mdadm: added /dev/sdf1 to /dev/md0 as 9
mdadm: added /dev/sdg1 to /dev/md0 as 10
mdadm: added /dev/sdh1 to /dev/md0 as 11
mdadm: added /dev/sdj1 to /dev/md0 as 0
mdadm: /dev/md0 assembled from 11 drives - not enough to start the array.

AND:

cat /proc/mdstat:

cat /proc/mdstat 
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : inactive sdj1[0](S) sdh1[11](S) sdg1[10](S) sdf1[9](S) sde1[8](S) sdc1[6](S) sdb1[5](S) sda1[4](S) sdm1[3](S) sdl1[2](S) sdk1[1](S)
      21488646696 blocks super 1.0
       
unused devices: <none>

Seems like every HDD got marked as a spare. Why would mdadm do this, and how can I convince mdadm that they are not spares?

Ok.  It seems you also need "--run".

Try:

mdadm --stop /dev/md0
mdadm -AfRv/dev/md0 /dev/sd[abcefghjklm]1

Also, what kernel version and mdadm version are you using?

Phil