Lost Array after reinstall

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    • Lost Array after reinstall

      reating a mirror raid

      The simplest example of creating an array, is creating a mirror.
      mdadm --create /dev/md/name /dev/sda1 /dev/sdb1 --level=1 --raid-devices=2 This will copy the contents of sda1 to sdb1 and give you a clean array. There is no reason why you can't use the array while it is copying (resyncing). This can be suppressed with the "--assume-clean" option, but you should only do this if you know the partitions have been wiped to null beforehand. Otherwise, the dead space will not be a mirror, and any check command will moan blue murder.I had to reinstall to fix some plugin issues and I created another issue. I have two mirrors, md0 & md1, both are RAID 0 arrays. After the reinstall I lost the RAID 1 array, but both RAID 0 arrays are still there:

      cat /proc/mdstat
      Personalities : [raid0]
      md1 : active raid0 sda[0] sdi[3] sdh[2] sdc[1]
      5371653120 blocks super 1.2 512k chunks

      md0 : active raid0 sdd[0] sdf[3] sdg[2] sdb[1]
      5371653120 blocks super 1.2 512k chunks


      mdadm --detail /dev/md*

      /dev/md0:
      Version : 1.2
      Creation Time : Wed May 30 14:07:02 2018
      Raid Level : raid0
      Array Size : 5371653120 (5122.81 GiB 5500.57 GB)
      Raid Devices : 4
      Total Devices : 4
      Persistence : Superblock is persistent

      Update Time : Wed May 30 14:07:02 2018
      State : clean
      Active Devices : 4
      Working Devices : 4
      Failed Devices : 0
      Spare Devices : 0

      Chunk Size : 512K

      Name : helptek-omv:0
      UUID : ed9156b7:78653ac0:1d5ad2e4:c013464c
      Events : 0

      Number Major Minor RaidDevice State
      0 8 48 0 active sync /dev/sdd
      1 8 16 1 active sync /dev/sdb
      2 8 96 2 active sync /dev/sdg
      3 8 80 3 active sync /dev/sdf
      /dev/md1:
      Version : 1.2
      Creation Time : Wed May 30 14:07:14 2018
      Raid Level : raid0
      Array Size : 5371653120 (5122.81 GiB 5500.57 GB)
      Raid Devices : 4
      Total Devices : 4
      Persistence : Superblock is persistent

      Update Time : Wed May 30 14:07:14 2018
      State : clean
      Active Devices : 4
      Working Devices : 4
      Failed Devices : 0
      Spare Devices : 0

      Chunk Size : 512K

      Name : helptek-omv:1
      UUID : 6ca14c0f:c8dfdb23:a62d00d7:288bae45
      Events : 0

      Number Major Minor RaidDevice State
      0 8 0 0 active sync /dev/sda
      1 8 32 1 active sync /dev/sdc
      2 8 112 2 active sync /dev/sdh
      3 8 128 3 active sync /dev/sdi

      I ran into this issue before and was able to recreate the RAID 1 array without losing any data. I don't remember what I did, but I think what I did was simply enter a few commands and I was able to get my files back. I was reading through the MDADM wiki and saw this:


      MDADM wiki wrote:

      Creating a mirror raid


      The simplest example of creating an array, is creating a mirror

      mdadm --create /dev/md/name /dev/sda1 /dev/sdb1 --level=1 --raid-devices=2This will copy the contents of sda1 to sdb1 and give you a clean array. There is no reason why you can't use the array while it is copying (resyncing). This can be suppressed with the "--assume-clean" option, but you should only do this if you know the partitions have been wiped to null beforehand. Otherwise, the dead space will not be a mirror, and any check command will moan blue murder.
      If I understand this correctly it won't wipe the devices and will copy from A to B. If thats the case i can move this along, but I don't want to do something that will cause loss of my data.

      Yes I'm aware this is not the most efficient setup, and I don't care. I built this out of scrap parts including the hard drives. And yes I should have backed up my data before the reinstall... but I didn't so lets skip that part.