mdadm RAID problem -- won't boot
Rick Bragg
rbragg at gmnet.net
Mon Aug 20 19:39:18 UTC 2012
> On Mon, Aug 20, 2012 at 1:36 PM, Rick Bragg <rbragg at gmnet.net> wrote:
>>
>> I am having a problem booting my system. My boot disk is not a raid array,
>> however, I do have 4 other disks making a raid 10 array that I mount at /mnt/md0.
>> My problem is that when I boot my system, I get to a point where it says it
>> it can't start the degraded array, and asks me if I want to start the degraded
>> array. If I say yes or no, it always drops me to a shell. At the shell, I do a
>> "cat /proc/mdadm" and I can see 2 arrays! One is /dev/md0 started, degraded with
>> only 3 of my disks (sda1, sdc1, sdd1.) The other array is /dev/md127 with the
>> other disk all by itself (sdb1) and not started. Again, I am booting from a
>> different disk entirely (sde1.) I tried to remove the md127 array altogether,
>> and
>> re-add sdb1 into the md0 array, and it syncs up fine. After syncing and seeing
>> that the md0 array is fine, I reboot. After rebooting, I get the same problem
>> over
>> and over again.
>> My question is:
>> How can I fix this so that I only have one array at /dev/md0 with all 4 disks
>> synced? Also, how can I bypass this and boot my system without any raid at all
>> so
>> I can fix that later? I am using ubuntu server 10.04 LTS.
>
> The use of md127 usually means that the array's recognized as a
> foreign array. Does "mdadm --examine" on sda1 and sdb1 return the same
> "local to host" value on the "Name" line?
>
> Did you zero the superblock before re-adding sdb1?
>
I didn't zero the superblock on anything. Should I zero it on sdb1?
for --examine, I'm seeing:
RaidDevice State
0 active sync /dev/sda1
1 faulty removed
2 active sync /dev/sdc1
3 active sync /dev/sdd1
4 spare /dev/sdb1
Not sure why sdb is a spare, and dev 1 is faulty removed...
Also, for mdadm --detail /dev/md0 I see:
RaidDevice State
0 active sync /dev/sda1
1 spare rebuilding /dev/sdb1
2 active sync /dev/sdc1
3 active sync /dev/sdd1
After the spare rebuilds and is active sync like the others, I usually reboot and I
get the same problem all over from the start. Do I need to somehow re-create the
entire array? or zero a superblock somewhere after this syncs?
Thanks again!
Rick
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