RAID degraded, partition missing from md0
Hey guys,
We're having a very weird issue at work. Our Ubuntu server has 6 drives, set up with RAID1 as follows: /dev/md0, consisting of: /dev/sda1 /dev/sdb1 /dev/md1, consisting of: /dev/sda2 /dev/sdb2 /dev/md2, consisting of: /dev/sda3 /dev/sdb3 /dev/md3, consisting of: /dev/sdc1 /dev/sdd1 /dev/md4, consisting of: /dev/sde1 /dev/sdf1 As you can see, md0, md1 and md2 all use the same 2 drives (split into 3 partitions). I also have to note that this is done via ubuntu software raid, not hardware raid. Today, the /md0 RAID1 array shows as degraded - it is missing the /dev/sdb1 drive. But since /dev/sdb1 is only a partition (and /dev/sdb2 and /dev/sdb3 are working fine), it's obviously not the drive that's gone AWOL, it seems the partition itself is missing. How is that even possible? And what could we do to fix it? My output of cat /proc/mdstat: Code:
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] Any help would be greatly appreciated! |
Hi,
it's not so unusual to have problems with just one partition on a disk. You can try to rebuild with the existing sdb, or you can replace the sdb and then rebuild. See for example http://www.howtoforge.com/replacing_..._a_raid1_array for the latter option. However, before doing anything make sure you are familiar with: https://raid.wiki.kernel.org/index.php/Linux_Raid Evo2. |
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Hi,
Quote:
Code:
mdadm --assemble --scan Evo2. |
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Actually, let me clarify - if I do a:
Code:
mdadm --assemble --scan Code:
mdadm --assemble /dev/md0 /dev/sda1 /dev/sdb1 |
I think its better to stop md device. What is output of mdadm --detail /dev/md0
Thanks |
I can't stop the device :(
Also, the / root filesystem is mounted on md0. The output you requested is: Code:
/dev/md0: |
I think if its showing removed that following command should recover
mdadm /dev/md0 -a /dev/sdb1 Thanks |
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I am unable to see any error message above . Ideally for replacing device , I follow
mdadm /dev/md0 -f /dev/sdb1 mdadm /dev/md0 -r /dev/sdb1 mdadm /dev/md0 -a /dev/sdb1 Thanks |
Quote:
Code:
mdadm: add new device failed for /dev/sdb1 as 2: Invalid argument |
Got the following results:
Code:
root@lia:~# mdadm /dev/md0 -f /dev/sdb1 |
Hate to bump a thread, but I still need help with this. Any advice, anyone? :)
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Hi,
mdadm doesn't seem to see /dev/sdb1 at all. I suggest you investigate its status with other tools. Eg fdisk Evo2. |
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