Soft RAID disappears after one disk is removed

    • OMV 4.x

    This site uses cookies. By continuing to browse this site, you are agreeing to our Cookie Policy.

    • Soft RAID disappears after one disk is removed

      I have soft RAID 1 created out of 2 WD 4TB hard drives for all my data, and I always taught that if one of them failed, everything will continue to work without any interruptions.
      And today I decided to test that and realized that nothing is working as I taught!
      I shut down my machine, took out the cables out of one of my disks and started the machine... and raid disappeared!, and because raid disappeared, all folders that are referencing locations on raid disk are now dead.
      So I shut down the machine, put back the cables for the disk that was missing earlier and voila, raid is back again. But I'm not sure that this is normal. Can someone confirm that that is not normal behavior? Raid should be there no matter if one disk is missing or not?
      Below on the left is the output from OMV with both disks present and on the right is output from OMV with one disk missing.
    • Your assumption is incorrect. The data is not lost in mirror mode, but the RAID is not functional unless you've defined a spare disk that immediatelly replaces the missing one.
      Absolutely no support through PM!

      I must not fear.
      Fear is the mind-killer.
      Fear is the little-death that brings total obliteration.
      I will face my fear.
      I will permit it to pass over me and through me.
      And when it has gone past I will turn the inner eye to see its path.
      Where the fear has gone there will be nothing.
      Only I will remain.

      Litany against fear by Bene Gesserit
    • Once upon I time I had IBM server that had hardware RAID1 set up, and when one of the two disks died, server haven't stopped working, it booted normally to Windows Server with notification that RAID1 should be repaired (by replacing failed disk).
      So I assumed that everything should continue to work without interruption, in this case with soft raid1 and OMV, but I guess that I was wrong.
      Thanks for the clarification.
    • TrickyTrix wrote:

      So I assumed that everything should continue to work without interruption, in this case with soft raid1 and OMV, but I guess that I was wrong.
      I wouldn't say wrong, soft raid and hardware raid are totally different, but to help you there is a thread here albeit the thread references a Raid5 the follow on in that thread will explain.
      Raid is not a backup! Would you go skydiving without a parachute?
    • TrickyTrix wrote:

      I read the thread you linked and it was indeed an interesting read.
      The reason I referenced the thread was to highlight the fact that simply 'pulling a drive' is not the same as a drive failing.

      In a hardware raid pulling a drive from a raid would allow the raid to continue to function, in a soft raid if you pulled a drive without rebooting the raid would still display clean. It's not until you reboot that the software knows that a drive is missing but in essence doesn't know what to do, hence it becomes inactive.

      If a drive fails in OMV's soft raid the raid would display clean/degraded, you can then remove the failed drive using the GUI add a clean drive and recover without the use of the command line.
      Raid is not a backup! Would you go skydiving without a parachute?