On Mon, 19 Aug 2013 07:48:20 +0000 [off-list ref] wrote:

Hey,

quoted

Strange.  I would definitely have expected one of those to start the
recovery.
Does anything appear in the kernel logs (e.g. output of 'dmesg')?

Please see the attaches boot.msg - from my perspective it only confirms the results
gained from the /proc/mdstat and mdadm output.

I guess I should have been more explicit.
It looks like you have just attached a log of what happened at boot.
I mean does anything appear in the dmesg output when you try to add the spare
device to the array.

To give some more information - her the mdadm.conf:

s15434194:~ # cat /etc/mdadm.conf
CREATE owner=root group=disk mode=0660 auto=yes

MAILADDR root

DEVICE containers partitions
ARRAY /dev/md1 level=raid1 num-devices=2 devices=/dev/sda1,/dev/sdb1
ARRAY /dev/md3 level=raid1 num-devices=2 devices=/dev/sda3,/dev/sdb3


Could it be that the problem lies in the order in the devices row? When I compare the working md1 and the non-working md3 array I see a difference in the mapping of devices to numbers:

No, the order is irrelevant.

The experiment below wouldn't change anything.

NeilBrown

For md1:

   Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       8       17        1      active sync   /dev/sdb1

For md3:

    Number   Major   Minor   RaidDevice State
       0       8       19        0      active sync   /dev/sdb3
       1       0        0        1      removed

       2       8        3        -      spare   /dev/sda3


Would this be worth a try (the disks need approx. 24 hours to reach the rebuild-state, so I'm reluctant to try without some hope) to do:

1. change the Array line in /etc/mdadm.conf for md3 to read (switching order):
ARRAY /dev/md3 level=raid1 num-devices=2 devices=/dev/sdb3,/dev/sda3
2. Remove the spare sda3
3. Zero the superblock of sda3
4. Add sda3 again to the array

?

Mit freundlichen Grüßen

Matthias Bläsing
Abt IT
KompetenzCenter

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