Mirror Raid from Synology to OMV

  • Hello,


    I searched the forums but couldn't find my answer and I want to be sure so I do not remove files by accident.

    Because my old Synology NAS was acting strange lately I took an old computer here and I set that up to use that as a NAS.


    The OS (OMV) is installed on an SSD and after the installation I disassembled my Synology to get my 2 hard disks, they are in RAID1 (Mirror).

    So I added them to the OMV system and when booting up again I see them in the "Software RAID". That's a good sign, isn't it? :)


    Then I went to "File Systems" and selected /dev/md127 and clicked "mount an existing file system" but I guess that's not good.

    Now I'm stuck because I can't see my data (files), what else do I have to do to get my files back.

    Do I also have to create the users like on my Synology and the groups etc?

  • chente

    Approved the thread.
    • Official Post

    If that Raid has been created in DSM it is probably not a standard Raid. As always, Synology does things its way. Then you should copy that data somewhere else and then wipe the disks in OMV to create a Raid again. If you really need a Raid, remember that Raid is NOT a backup (google that phrase).

  • andlinux From your screenshots, OMV has found a MIRROR RAID and mounted the filesystem it contains, so you should be able to access your data. OMV does not by default have any kind of on screen file browser unless you install the core "file browser plugin" or use "wetty" to explore the filesystem on OMV, or connect to OMV via ssh. .

    • Official Post

    From your screenshots, OMV has found a MIRROR RAID and mounted the filesystem it contains, so you should be able to access your data. OMV does not by default have any kind of on screen file browser unless you install the core "file browser plugin" or use "wetty" to explore the filesystem on OMV, or connect to OMV via ssh. .

    You're right, I didn't stop to look at the images and it seems like the Raid was assembled satisfactorily. Therefore, it would only be necessary to create users, permissions, shared resources, etc. Anyway I would redo that Raid, Synology can make strange configurations in a Raid and the problems can arrive later.

    • Official Post

    This is simply a bad idea to continue to use this, why?


    1) The two drives shown in raid management are displayed as /dev/sdb3 and dev/sdc3, the 3 defines a partition, OMV does not use partitions to create arrays it uses the 'full block device' (the whole drive). Whilst an array can be created on the cli using partition/s the problem comes when trying to replace a failed drive/partition within an array


    2) AFAIK DSM uses storage pools then volumes before creating an array, that can either be hybrid or a standard array Raid0, 1, 5, 6, etc


    3) Continuing using this would initially be OK, until a drive fails and requires replacing, you're than into another can of worms trying to replace a drive within the array that was not created in OMV's GUI


    4) Put the drives back in the Synology, back up the data you cannot afford to lose, then add the drives back to OMV, secure wipe them and create an array within OMV's GUI

    • Official Post

    2) AFAIK DSM uses storage pools then volumes before creating an array, that can either be hybrid or a standard array Raid0, 1, 5, 6, etc

    One of the things that DSM does, if it hasn't changed lately, is create a partition on each disk where the operating system is hosted. The rest of the disk houses the partition with which the Raid is created.

  • I must confess I didn't notice the /dev/sdX3. For the more adventurous you could fail one drive of the RAID mirror. Wipe the failed drive to use in creating a new degraded array and then to copy the data on the original (now degraded array) to the new array. Finally you delete the original array, wipe the now spare drive and add that to the new array. You could, if you wanted move from a MD RAID to a BTRFS when doing something like this. All depends on how precious data is, in which case the OP really should have had backup of the Synology data in the first case.

  • To be sure I have ordered 2 new hard disks, I will put these in my new system (OMV)

    and I'm gonna copy all over from the Synology to the new system.

    This seems in my view the best thing to do.

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