Missing data in my RAID after système upgrade

[Hrist]

Hello the Helios4 community,

This is quite the story and I may have messed up at multiple steps, especially since I did not backup my RAID data (please don't go too hard on me for this, it's difficult task for me since I don't have enough space on any of my computer to do so), but I hope that at least you can help me to salvage some data.

Short story:

• I flashed my sd cart to upgrade to the last armbian available (I was on armbian 9)
• After some hurdle I finally could had a stable boot and installed OpenMediaVault
• When looking for my RAID 10 data I found that they were gone, replaced by what looks like a linux system, here's its current content :

root@helios4:~# ls /mnt/md0/
aquota.group  boot  export  lost+found  opt   run      srv  usr
aquota.user   dev   home    media       proc  sbin     sys  var
bin           etc   lib     mnt         root  selinux  tmp

I have no idea where those data come from, the only mdadm command I did were the one to import an existing raid, I did not use mkfs or any other command that could alter, format, erase, … my data.

 

Full story:

Yesterday I wanted to upgrade my helios4 system.

First I upgraded my kernel to the last legacy version avaiable following this post: https://blog.kobol.io/2020/03/13/armbian-new-release/, this completed successully

After that I followed what was at the end of this post: https://blog.kobol.io/2019/08/01/armbian-new-release/, to upgrade from Debian 9 (Stretch) to 10 (Buster), it was quite long  completed it successfully.
Then I had a stupid idea, can I upgrade my kernel from the LEGACY branch to the CURRENT one ? This broke my system boot.

 

With no easily available way to fix my system I decided to flash my sd card to do a clean install. Before that I did a simple copy (cp) of my card content to one of my computer, so I've all my old conf, for example the one in /etc/, available.
I downloaded the latest os image in https://wiki.kobol.io/download/#latest-os-images, flashed my SD card using balena-etcher, and rebooted my system.
After that I flashed the SD card three more times due to mistakes of mine:

• first after I installed Samba alongside OMV using armbian-config (instead of letting OMV handle it), leading to a boot error.
• second after I used mdadm commands (to import an existing raid) after OMV installation, leading to OMV scripts conflicting with what was saved in my mdadm conf.
  • When using OMV web interface at this step, before crashing it, there was already something that really worried me since my RAID10 drive was reported to only use 1.7Go of the available 5.2To (I had more than 3To of data on it).
• lastly I reflashed in a desparate attempt to see if following the import an existing raid procedure before installing OMV would yield a better result.

That's were I'm now, with my data still replaced by this strange linux instal and OMV still to be installed.

 

For information here's my ARRAY line on my old mdadm.conf:

ARRAY /dev/md0 metadata=1.2 name=helios4:0 UUID=9320d0fb:d59774c6:f7f2746c:476c3ce9
And the one in my new ():
ARRAY /dev/md/helios4:0 metadata=1.2 name=helios4:0 UUID=9320d0fb:d59774c6:f7f2746c:476c3ce9

 

If you have any question don't hesitate to ask it :).

 

Hope you can help.