On 28/10/17 19:36, Jun-Kai Teoh wrote:
Hi all,
Hope this email is going to the right place.
I'll cut to the chase - I added a drive to my RAID 5 and was resyncing
when my machine was abruptly powered down. Upon booting it up again,
my RAID array is now missing.
I've seen Mark's replies, so ...
I've followed the instructions that I've found on the wiki, and it
hasn't solved my issues, but it's given me a sense of the things that
I'm hoping can help you guys help me troubleshoot.
Found where? Did you look at the front page? Did you look at "When
things go wrogn"?
My array can't be assembled. It tells me that the superblock on
/dev/sda doesn't match the others.
/dev/sda thinks the array has 7 drives
/dev/sd[bcefghi] thinks the array has 8 drives
The event count tells me sda was kicked out of the array a LONG time ago
- you were running a degraded array, sorry.
/dev/sda was not being reshaped
/dev/sd[bcefghi] has reshape position data in the raid.status file
both /dev/sda and /dev/sdh think their device role is Active device 2
I can't bring /dev/md126 back up with sd[bcefghi] as it'll tell me
that there are 6 drives and 1 rebuilding, not enough to start the
array
My mdadm.conf shows a /dev/dev/127 with very minimal info in it - does
not look right to me.
I haven't zeroed the superblock, nor have I tried a clean-assemble
either. I saw the wiki say I should email the group if I've gotten
that far and I'm panicking and nothing's working. So...
Help me out, pretty please?
Okay, I *think* you're going to be okay. The powerfail brought the
machine down, and because the array was degraded, it wouldn't
re-assemble. Like Mark, I'd wait for the experts to get on the case on
Monday, but what I think they will advise is
One - --assemble --force [bcdefghi] - note do NOT include the failed
drive a. This will fire off the reshape again. BUT. On a degraded array
you have no redundancy!!!
Two - ADD ANOTHER DRIVE TO REPLACE SDA !!!
I don't know how to read the smartctl statistics (and I don't know which
one is sda!), but if I were you I would fire off a self-test on sda to
find out whether it's bad or not. It may have been kicked out by a
harmless glitch, or it may be ready to fail permanently. But be prepared
to shell out for a replacement. In fact, I'd go out and get another
drive right now. If sda turns out to be okay, you can go to a 9-drive
raid-6.
To cut a long story short, I think you've been running with a degraded
array for a long time. You should be able to force-assemble it no
problem but you need to fix it asap. And then you should go raid-6 to
give you a bit extra safety and set up scrubbing! Again, I'll let the
experts confirm, but I think going from 8-drives-degraded to
9-drive-raid-6 in one step is probably better than recovering your raid
5 and then adding another drive to go raid 6.
Just wait for the experts to confirm this and then I think you'll be
okay. On the good side, you do have proper raid drives - WD Reds :-)
Cheers,
Wol
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