On 11/4/19 12:11 pm, Mark Wagner wrote:
On Wed, Apr 10, 2019 at 6:36 PM Adam Goryachev
<mailinglists@xxxxxxxxxxxxxxxxxxxxxx> wrote:
On 11/4/19 6:44 am, Mark Wagner wrote:
I've got a server with a five-disk RAID-6 array. Last night, power to
the server went out, and when I powered it back up, one of the disks
failed. During bootup, the RAID array was assembled as an inactive
four-disk RAID-0 array with four spares rather than the expected
degraded RAID-6, and manually assembling the array doesn't give a
different result. Any idea how I can get my array back? There
doesn't appear to be anything wrong with the four remaining disks, it
simply isn't working.
Steps I used to manually assemble the array:
# mdadm --stop /dev/md2
# mdadm --assemble --verbose /dev/md2 /dev/sd[abcd]
mdadm: looking for devices for /dev/md2
mdadm: /dev/sda is identified as a member of /dev/md2, slot 1.
mdadm: /dev/sdb is identified as a member of /dev/md2, slot 0.
mdadm: /dev/sdc is identified as a member of /dev/md2, slot 3.
mdadm: /dev/sdd is identified as a member of /dev/md2, slot 4.
mdadm: added /dev/sda to /dev/md2 as 1
mdadm: no uptodate device for slot 2 of /dev/md2
mdadm: added /dev/sdc to /dev/md2 as 3
mdadm: added /dev/sdd to /dev/md2 as 4
mdadm: added /dev/sdb to /dev/md2 as 0
mdadm: /dev/md2 assembled from 4 drives - need all 5 to start it (use
--run to insist).
Did you do what the log told you to do?
mdadm --stop /dev/md2
mdadm --assemble --verbose --run /dev/md2 /dev/sd[abcd]
mdadm --assemble --help says this:
--run -R : Try to start the array even if not enough devices
for a full array are present
It's currently showing as an inactive RAID-0 array. I'm worried that
using "--run" will assemble them as an *active* RAID-0 array, with the
corresponding loss of data. I've got backups, but I really don't want
to need to use them.
That's just because it isn't active, so the details haven't been loaded
yet. There was a post on this list a few months back reporting this
issue. Just start the array.
If you are unsure, and want to be safe, then look at the RAID wiki, and
use overlay devices, then start the array on the overlay devices.
Regards,
Adam
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Adam Goryachev Website Managers www.websitemanagers.com.au
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