Raid 1 missing

  • After having removed and mounted a disk (sdc) on a different computer, my raid 1 array now does not appear in the web GUI under raid management when returned to my server.



    cat /proc/mdstat

    Code
    Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
    md0 : inactive sdb[0](S)
    2930135512 blocks super 1.2
    unused devices: <none>


    blkid

    Code
    /dev/sda1: UUID="b40a2842-935f-424f-be3c-8eff091e7a4b" TYPE="ext4" PARTUUID="326a2e34-01"
    /dev/sda5: UUID="31ed5f71-3b23-4db7-8d75-a7aefa980882" TYPE="swap" PARTUUID="326a2e34-05"
    /dev/sdb: UUID="9481f885-48b8-5b55-b930-b86b3e152e6c" UUID_SUB="1350e551-f6bc-41e3-f2c4-39f54de07cf5" LABEL="openmediavault:Raid1" TYPE="l inux_raid_member"
    /dev/sdd1: LABEL="1TBDrive" UUID="0163461d-12a9-47eb-91ea-f7e3f245aaeb" TYPE="ext4" PARTUUID="8e15da09-0f0e-4dda-8fe9-323cb7a9272a"


    fdisk -l | grep "Disk "


    Code
    Disk /dev/sda: 29.5 GiB, 31675383808 bytes, 61865984 sectors
    Disk identifier: 0x326a2e34
    Disk /dev/sdb: 2.7 TiB, 3000592982016 bytes, 5860533168 sectors
    Disk /dev/sdd: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors
    Disk identifier: A2B116B8-5357-45A5-9483-9C88D1D51CFD
    Disk /dev/sdc: 2.7 TiB, 3000592982016 bytes, 5860533168 sectors


    cat /etc/mdadm/mdadm.conf



    mdadm --detail --scan --verbose


    Code
    INACTIVE-ARRAY /dev/md0 num-devices=1 metadata=1.2 name=openmediavault:Raid1 UUID=9481f885:48b85b55:b930b86b:3e152e6c
    devices=/dev/sdb


    As far as i can tell the device sdb still is listed as a raid member. However, in trying to rebuild the array (by adding sdc) gives the following error:

    Code
    root@openmediavault:~# mdadm --assemble /dev/md0 /dev/sdb /dev/sdc/
    mdadm: /dev/sdb is busy - skipping
    mdadm: cannot open device /dev/sdc/: Not a directory
    mdadm: /dev/sdc/ has no superblock - assembly aborted


    Keep in mind that im new to OMV and mdadm, just in case the above command is not how you are supposed to do it :P . Tried following tips found here, however to no avail. Any help is appreciated!

  • You need to stop md0 before assembling it. I would use the force and verbose flags when assembling.

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  • Cool! Didnt know that. When i try that i get:

    Code
    root@openmediavault:~# mdadm --stop /dev/md0
    mdadm: stopped /dev/md0
    root@openmediavault:~# mdadm --assemble --force --verbose /dev/md0 /dev/sdb /dev/sdc/
    mdadm: looking for devices for /dev/md0
    mdadm: cannot open device /dev/sdc/: Not a directory
    mdadm: /dev/sdc/ has no superblock - assembly aborted


    sdc - "not a directory". Do i need to create a filesystem first on sdc or something? Also it seems the superblock is missing. I know that there is a --zero-superblock flag, however no entirely sure how to use it. Thanks for the help so far!

  • Ahh rookie mistake :/


    However, now im getting this:

    Code
    root@openmediavault:~# mdadm --assemble --force --verbose /dev/md0 /dev/sdb /dev/sdc
    mdadm: looking for devices for /dev/md0
    mdadm: No super block found on /dev/sdc (Expected magic a92b4efc, got 00000000)
    mdadm: no RAID superblock on /dev/sdc
    mdadm: /dev/sdc has no superblock - assembly aborted
  • In that case, I usually wipe the drive. It will have to resync. I would think about dumping the raid idea and using rsync or something else to sync the two drives.

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  • So wiping sdc or sdb? In other words, there is no way to sync those two drives back to how they were? Im not sure i understand the point of raid 1 then ?( . If sdb is dependent on something on sdc, wouldnt that defeat the purpose of raid, in that i cannot restore it after a potential drive failure? Oh well, the data wasnt all that important any way, guess i will wipe and start from fresh. Thanks for the help!

  • So wiping sdc or sdb?

    Wipe sdc since it doesn't know that it is a member of the array anymore.


    there is no way to sync those two drives back to how they were?

    That is what assembling does.

    Im not sure i understand the point of raid 1 then

    It is about availability and redundancy but if there is something is wrong with your drive, either it needs to be fixed or replaced. Then a resync needs to happen. If you are trying to use raid as backup in case a drive fails, that is the wrong use.


    If sdb is dependent on something on sdc, wouldnt that defeat the purpose of raid, in that i cannot restore it after a potential drive failure?

    sdb isn't dependent on sdc but the array is warning you that there is a problem. You can start a degraded array with one drive but it can be dangerous. In your case, I would start the array in degraded mode with just one drive and wipe/format the other drive with a filesystem. Then rsync the data to it. Then stop the array and do the same format to the other drive. Setup an rsync job to keep the drives sync'd.

    omv 5.5.1 usul | 64 bit | 5.4 proxmox kernel | omvextrasorg 5.3.3
    omv-extras.org plugins source code and issue tracker - github


    Please read this before posting a question.
    Please don't PM for support... Too many PMs!

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