Hi folks:

  We've seen a "failure" ... whereby something like 10 drives
simultaneously dropped out of a RAID6 array.  The drives haven't
failed, we can see them, see the metadata on them, see the RAID
partitions ... what we can't do is reassemble it into a RAID, as some
of the drives are note listed as "Active"


root@dv4:~# mdadm -v --assemble /dev/md0
mdadm: looking for devices for /dev/md0

...

mdadm: /dev/sdr3 is identified as a member of /dev/md0, slot 14.
mdadm: /dev/sdy3 is identified as a member of /dev/md0, slot 15.
mdadm: /dev/sdx3 is identified as a member of /dev/md0, slot -1.
mdadm: /dev/sdw3 is identified as a member of /dev/md0, slot 21.
mdadm: /dev/sdv3 is identified as a member of /dev/md0, slot 20.
mdadm: /dev/sdu3 is identified as a member of /dev/md0, slot 19.
mdadm: /dev/sdt3 is identified as a member of /dev/md0, slot 18.
mdadm: /dev/sds3 is identified as a member of /dev/md0, slot 17.
mdadm: /dev/sdq3 is identified as a member of /dev/md0, slot 7.
mdadm: /dev/sdp3 is identified as a member of /dev/md0, slot 6.
mdadm: /dev/sdo3 is identified as a member of /dev/md0, slot 5.
mdadm: /dev/sdn3 is identified as a member of /dev/md0, slot 4.
mdadm: /dev/sdm3 is identified as a member of /dev/md0, slot 3.
mdadm: /dev/sdl3 is identified as a member of /dev/md0, slot 2.
mdadm: /dev/sdk3 is identified as a member of /dev/md0, slot 1.
mdadm: /dev/sdj3 is identified as a member of /dev/md0, slot 0.
mdadm: /dev/sdc3 is identified as a member of /dev/md0, slot 9.
mdadm: /dev/sdi3 is identified as a member of /dev/md0, slot 16.
mdadm: /dev/sdh3 is identified as a member of /dev/md0, slot 13.
mdadm: /dev/sdg3 is identified as a member of /dev/md0, slot -1.
mdadm: /dev/sdf3 is identified as a member of /dev/md0, slot 12.
mdadm: /dev/sde3 is identified as a member of /dev/md0, slot 11.
mdadm: /dev/sdd3 is identified as a member of /dev/md0, slot 10.
mdadm: /dev/sdb3 is identified as a member of /dev/md0, slot 8.
mdadm: added /dev/sdj3 to /dev/md0 as 0
mdadm: added ...
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Using the --force option to assemble should do it.

You may need to stop the array in it's current state first, I'm not sure.

Regards,

Richard


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