raid 5 to raid 6 conversion when adding drive

  • Hello,


    I am looking to convert my current raid 5 array with 5x8TB drives into a raid 6 with 6x8TB drives. I found this guide in a post from a few years ago and was wondering if this would work with OMV and would show in the gui after it is complete?


    http://ewams.net/?date=2013/05…g_RAID5_to_RAID6_in_mdadm


    Thanks for any assistance, I know a lot of you guys dont like RAID but I would like to add an additional parity disk to help against physical drive failures while maintaining the data in the existing raid.

    • Official Post

    I found this guide in a post from a few years ago and was wondering if this would work with OMV and would show in the gui after it is complete?

    That should work.


    I know a lot of you guys dont like RAID

    I don't mind raid at all. I just think most OMV users don't need it because uptime is not critical for a home user (or even some small businesses). We also push against it when people think it is backup.

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  • That should work.

    I don't mind raid at all. I just think most OMV users don't need it because uptime is not critical for a home user (or even some small businesses). We also push against it when people think it is backup.

    awesome, thanks now just waiting for a drives to be on sale then I will give it a go.

    • Official Post

    When it is completed, will omv web gui be updated to show the new version of raid?

    yes

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  • instead of adding my 2 new disks to my raid 5 array via cli, using the following command as shown in the guide.


    mdadm --add /dev/md0 /dev/sda


    I instead used the gui and used the grow button on the raid array which I assume makes them functioning members of the raid instead of spares. Is there any way for me to reverse or undo this or will I have to buy another disk and follow the instructions correctly. Correctly the raid array is reshaping.

    • Official Post

    I instead used the gui and used the grow button on the raid array which I assume makes them functioning members of the raid instead of spares. Is there any way for me to reverse or undo this or will I have to buy another disk and follow the instructions correctly. Correctly the raid array is reshaping.

    Just to be clear, you added both with the grow button and now you want to use one of the disks added to create raid 6 instead? What is the output of: cat /proc/mdstat

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  • Above is the output, and you are correct. I would like to use one of the disks that I added via grow to convert the raid 5 to a raid 6.

    • Official Post

    Unfortunately, using the grow button to add both disks is doing exactly what it is supposed to. You will have to wait for the array to get done reshaping and then you will have to reduce it by one disk (not something I like to do) to make it raid 6. I really hope you have backup if you try to reduce it.

    omv 7.0.5-1 sandworm | 64 bit | 6.8 proxmox kernel

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  • So i followed the process and everything looked to be going as expected. I got an email that the spare drive has failed. Is this just part of the process of mdadm adding it to the raid?

  • The new disk sdj, is also no longer showing up in the disks tab. Should I power down the server and confirm it is cabled firmly or do i have to wait for something to happen with the reshaping?


    Also adding what seems to be the relevant data from the syslog. Those messages continue for another minute or so then stop. It would go over the character limit if I add them all.

  • So at this point the reshape has stayed at 0% for the past 8 hours. Is it safe to assume that because the disk failed, it will not complete? If it will not complete, am I safe to power down and confirm the cabling of the drive to see if I can restore its functionality? Anything special I need to do on the OMV side to try to revive this brand new drive?

    • Official Post

    Hope you have a backup but this is unfamiliar territory for me. It *seems* that the reshape has not started. So, I would imagine you could power down to check cables, etc.

    omv 7.0.5-1 sandworm | 64 bit | 6.8 proxmox kernel

    plugins :: omvextrasorg 7.0 | kvm 7.0.13 | compose 7.1.4 | k8s 7.1.0-3 | cputemp 7.0.1 | mergerfs 7.0.4


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    • Official Post

    Is there someone else who might know more?

    google :) I do know there is no "good" way to stop a reshape You can suspend it with something like echo "idle" > /sys/block/md127/md/sync_action followed by a reboot but I don't think anyone is going to give you a solution that is 100% safe.

    omv 7.0.5-1 sandworm | 64 bit | 6.8 proxmox kernel

    plugins :: omvextrasorg 7.0 | kvm 7.0.13 | compose 7.1.4 | k8s 7.1.0-3 | cputemp 7.0.1 | mergerfs 7.0.4


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  • I rebooted and the "faulty" drive is showing up but the raid will not come up. Any ideas on what to try to bring the raid back up?

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