I have a RAID5 array consisting of 3 identical 2TB drives. Suddenly GRUB wouldn't boot anymore and gave the error out of disk.

Eventually booted a livecd and ran some mdadm commands:

mdadm --examine /dev/sda1 gives no md superblock detected on /dev/sda1. But when examining /dev/sdb1 and /dev/sdc1/ gives the output in the attached photo's.

<code>mdadm --examine sdb1</code> <code>mdadm --examine sdc1</code>

Any help in solving or diagnosing this problem would be greatly appreciated. Thanks!

  • Screenshots, seriously? You have two disks there, can't you just assemble it? Error messages? – frostschutz Feb 26 '15 at 21:54
  • Instead of screenshots you can always start a sshd from your live-system, remote-login and then copy'n'paste the terminal contents as text. Also, don't forget to look at /proc/mdstat. – maxschlepzig Feb 26 '15 at 21:57
  • 1
    Show the output of cat /proc/partitions – wurtel Feb 27 '15 at 10:43
  • cat /proc/partitions gives the following output: Major minor #blocks Name 8 32 1953514584 sdc 8 33 1953513472 sdc1 8 16 1953524584 sdb 8 17 1953523472 sdb1 8 0 1953514584 sda 8 1 1953513472 sda1 8 48 7574304 sdd 8 49 7573280 sdd1 I am sorry for the mess, I can not get the right lay out of the table in this comment box... – Sander Mar 18 '15 at 18:22

Normally you'd do mdadm --assemble --scan /dev/md0 --name server:0 and that would assemble the array, or maybe tell you to mdadm --run /dev/md0 to assemble it degraded. You can also explicitly give the devices instead of using --scan.

Then you can get your data off (or add a drive to rebuild).

That should work. Of course, something happened to erase the superblock off of one of your drives; you should find out what it was. It may have caused other damage.

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