Raid6 Issue

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    • Raid6 Issue

      Hey guys, some help would be appreciated :)
      So today I thought I'd check if my server case and motherboard support hot-swappable hdd's. What I wanted to accomplish by this is the knowledge that if I had to put another hard drive in, I wouldn't have to offline the system.
      So I went in, pulled out a hard drive (it's a front loading case with bays), nothing shut down and I did a small victory dance. But then I got an email the nas.

      "A DegradedArray event had been detected on md device /dev/md0."

      Now I can't seem to fix the issue.
      Under the 'raid management' tab it's showing the array as "Clean, degraded" and here the array details:

      Raid Devices : 5
      Total Devices : 4

      State : clean, degraded
      Active Devices : 4
      Working Devices : 4
      Failed Devices : 0
      Spare Devices : 0

      Number Major Minor RaidDevice State
      0 8 16 0 active sync /dev/sdb
      1 0 0 1 removed
      2 8 32 2 active sync /dev/sdc
      3 8 64 3 active sync /dev/sde
      4 8 80 4 active sync /dev/sdf

      It's showing the drive as 'removed' yet it's coming up in 'Physical Disks'.

      Any ideas?
    • Re: Raid6 Issue

      There is a "Recover" Button you can try. Maybe you need to wipe your disk (the one which is no more in your raid) or replace it with a new one.
      Then you should be able to recover it. If your wiped / new disk does not show up in the recover dialog, please post the output of

      Source Code

      1. blkid
      2. cat /proc/mdstat
      OMV stoneburner | HP Microserver | 256GB Samsung 830 SSD for system | 4x 2TB in a RAID5
      OMV erasmus| Odroid XU4 | 5TB Data drive | 500GB Backup drive
    • Re: Raid6 Issue

      Thank you for responding. The Recover button was not the way out. The lost disk did not show up in the list of available devices. After some reading and trial-and-error I managed to recover my RAID by re-adding the lost disk with the following command:

      Source Code

      1. mdadm md0 -a /dev/sdc/

      It took quite some time to recover my RAID, but now everything is working fine again. I do not have a clue what caused the disk to drop out of the RAID, so I hope this was a one time incident.
    • Re: Raid6 Issue

      A disk should not be dropped - usually. Maybe it is damaged? I would test this disk with S.M.A.R.T. for example.

      Recovering would have been the next step. But you fixed it by your own - nice! :)
      OMV stoneburner | HP Microserver | 256GB Samsung 830 SSD for system | 4x 2TB in a RAID5
      OMV erasmus| Odroid XU4 | 5TB Data drive | 500GB Backup drive