[RAID1] not assembling after move to other hardware

  • Hello gents,


    due to power consumption I decided to move a 2 disks raid1 array to another machine - that is pretty power efficient.
    There was a good review about this setup: Technikaffe: ASROCK Q1900 & openmediavault


    Some history


    The array consists of 2 Seagate 4TB disks. It was initially created on OMV 2.
    Later I had to re-install OMV 3 on the machine and the array was recognized when using:


     mdadm --assemble --scan 


    What happend now

    Based on the good experience with the last "move", I just shutdown the old machine.
    After that I removed the disks and put them into the new machine.


    But the new machine does not:


     root@files:~# mdadm --assemble --scan 
     mdadm: No arrays found in config file or automatically 


    So I gave it a try to force devices:


     root@files:~# mdadm --assemble /dev/md0 /dev/sdc /dev/sdd 
     mdadm: Cannot assemble mbr metadata on /dev/sdc 
     mdadm: /dev/sdc has no superblock - assembly aborted 


    What I found so far

    There seem to be issues in ASROCKs firmware. At least I understood this answer in that way: [RAID5] Missing superblocks after restart


    The output of blkid is this:


     root@files:~# blkid 
     /dev/sda1: UUID="65c2b8e4-e0bc-41d4-92e4-33076b4196f6" TYPE="ext4" PARTUUID="dd31c21e-01" 
     /dev/sda5: UUID="03dde5e4-cac1-43e1-a1c5-10b3a9d2d30a" TYPE="swap" PARTUUID="dd31c21e-05" 
     /dev/sdb1: UUID="54e0c731-7fb2-43d4-a41a-da6bdc1752bf" TYPE="ext4" PARTUUID="22560a85-2147-45cf-85e3-c14f3deaed9c" 
     /dev/sdc: PTUUID="2d2393b9-19b2-47d4-bc70-94434b5c7b5b" PTTYPE="gpt" 
     /dev/sdd: PTUUID="c9e13f03-1aac-483f-97cb-f4f3139b0830" PTTYPE="gpt" 



    ... with /dev/sdc and /dev/sdd being the disks in question. So no additional information here.


    The output of fdisk -l does not help that much:


    root@files:~# fdisk -l /dev/sdc /dev/sdd 

     Disk /dev/sdc: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors 
     Units: sectors of 1 * 512 = 512 bytes 
     Sector size (logical/physical): 512 bytes / 4096 bytes 
     I/O size (minimum/optimal): 4096 bytes / 4096 bytes 
     Disklabel type: gpt 
     Disk identifier: 2D2393B9-19B2-47D4-BC70-94434B5C7B5B 


     Disk /dev/sdd: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors 
     Units: sectors of 1 * 512 = 512 bytes 
     Sector size (logical/physical): 512 bytes / 4096 bytes 
     I/O size (minimum/optimal): 4096 bytes / 4096 bytes 
     Disklabel type: gpt 
     Disk identifier: C9E13F03-1AAC-483F-97CB-F4F3139B0830 


    The output of gdisk -l does not have additional information (output is the same as for /dev/sdd):


     root@files:~# gdisk -l /dev/sdc 
     GPT fdisk (gdisk) version 0.8.10 

     Partition table scan: 
      MBR: protective 
      BSD: not present 
      APM: not present 
      GPT: present 

     Found valid GPT with protective MBR; using GPT. 
     Disk /dev/sdc: 7814037168 sectors, 3.6 TiB 
     Logical sector size: 512 bytes 
     Disk identifier (GUID): 2D2393B9-19B2-47D4-BC70-94434B5C7B5B 
     Partition table holds up to 128 entries 
     First usable sector is 34, last usable sector is 7814037134 
     Partitions will be aligned on 2048-sector boundaries 
     Total free space is 7814037101 sectors (3.6 TiB) 

     Number Start (sector) End (sector) Size Code Name 


    The output of mdadm --examine is strange as well (output is the same for /dev/sdd):


     root@files:~# mdadm --examine /dev/sdc 
     /dev/sdc: 
      MBR Magic : aa55 
     Partition[0] : 4294967295 sectors at 1 (type ee) 


    What I have at hand


    I have some older mdadm --examine output for both drives.
    I have the mdadm.conf from the old machine.
    I have the old machine, but I did not find addition useful metadata - I probably did not look for the right stuff.


    How to proceed to access data on these disks?


    Thanks in advance and best regards

    ASROCK Q1900DC-ITX - 8 GB - 2x Seagate 4 TB - Samsung 500 GB system drive - OMV 3.0.86

  • I just want to add the output requested in the pinned thread Degraded or missing raid array questions


    I hope this gives additional information.


    Best regards

    ASROCK Q1900DC-ITX - 8 GB - 2x Seagate 4 TB - Samsung 500 GB system drive - OMV 3.0.86

  • I read a lot about smart behavior of mdadm when trying to recover/restore a raid 5 array when using --create.


    I was curious if this is working as well for raid 1 arrays. So I created a similar setup in a VM and did some tests ...
    It seems to me that this is working for raid 1 as well.


    So I gave it a try on one of my disks.
    I did the steps shown below.

    Zitat von dd should not be necessary ...

    dd if=/dev/zero of=/dev/sdX bs=512 count=1
    sgdisk --zap-all /dev/sdX


    shutdown -r 0

    Zitat von crossing fingers on this one ...

    mdadm --create /dev/md0 --raid-devices=2 --level=1 /dev/sdc missing

    Zitat von make the result accessible ...

    mkdir /srv/dev-disk-by-id-ata-ST4000DM000-1F2168_Z303RQLY
    mount /dev/md0 /srv/dev-disk-by-id-ata-ST4000DM000-1F2168_Z303RQLY/


    I could verify the file system is there.
    After downloading a single file to my local machine (laptop), all seems fine.


    But how to proceed now?


    I would like to avoid this raid 1 in the future. When setup some years ago, the presumptions were wrong ...
    Now there was trouble, that I would not have without it.


    Thanks for any comments and recommendations.


    Best regards

    ASROCK Q1900DC-ITX - 8 GB - 2x Seagate 4 TB - Samsung 500 GB system drive - OMV 3.0.86

  • Hello flmaxey,


    thanks for your reply.


    I read about ZFS and mirroring. Protection against bitrot is nice.
    I did not decide yet, how to go on.


    To document the whole story, please read below what the next steps have been.


    Next steps in my story


    I cleaned the second disk:

    Zitat von ... using this command:

    dd if=/dev/zero | dd of=/dev/sdd


    After creating a new file system, I copied all content from the degraded array to sdd.


    Best regards

    ASROCK Q1900DC-ITX - 8 GB - 2x Seagate 4 TB - Samsung 500 GB system drive - OMV 3.0.86

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