I recently lost my NAS and am trying to recover the data in my RAID. The disks are fine, its just the NAS hardware that stopped booting and I can't get any support as its discontinued.

I attached the disks to my Ubuntu machine and can see the following info:

sudo mdadm --detail /dev/md126
           Version : 1.2
     Creation Time : Sun Jan 10 09:57:09 2016
        Raid Level : raid5
        Array Size : 8776244352 (8.17 TiB 8.99 TB)
     Used Dev Size : 2925414784 (2.72 TiB 3.00 TB)
      Raid Devices : 4
     Total Devices : 4
       Persistence : Superblock is persistent

       Update Time : Fri May  6 07:03:58 2022
             State : clean 
    Active Devices : 4
   Working Devices : 4
    Failed Devices : 0
     Spare Devices : 0

            Layout : left-symmetric
        Chunk Size : 64K

Consistency Policy : resync

              Name : 0e342a28:data-0
              UUID : c1d1d0bb:08037d20:54ea1137:054d8bb7
            Events : 748

    Number   Major   Minor   RaidDevice State
       0       8       67        0      active sync   /dev/sde3
       1       8       51        1      active sync   /dev/sdd3
       2       8       35        2      active sync   /dev/sdc3
       3       8       19        3      active sync   /dev/sdb3

However, mdadm.config is emtpy and running the usual --scan commands doesn't return any results. I have tried using -assamble while passing on all disks as parameters but I get this result:

sudo mdadm --assemble /dev/md126 /dev/sdb3 /dev/sdc3 /dev/sdd3 /dev/sde3mdadm: /dev/sdb3 is busy - skipping
mdadm: /dev/sdc3 is busy - skipping
mdadm: /dev/sdd3 is busy - skipping
mdadm: /dev/sde3 is busy - skipping

I just want to get it mounted so that I can copy the data to the new NAS. Can anyone help with this?

Thanks, Alex

Edit 1: as per suggestion in comments, I have checked it with file:

sudo file -sL /dev/md126
/dev/md126: BTRFS Filesystem label "0e342a28:data", sectorsize 4096, nodesize 32768, leafsize 32768, UUID=d9f1e416-0a37-4425-9037-a35e229ba477, 8453121372160/8986874216448 bytes used, 1 devices
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  • It looks like it is assembled (as /dev/md126) but not mounted - have you tried something like sudo file -sL /dev/md126 to see if it contains a recognized filesystem? yesterday
  • OK so have you tried mounting it manually? sudo mkdir -p /mnt/nas && sudo mount -o ro /dev/md126 /mnt/nas for example? What are the error messages (if any)? What version of Ubuntu are you using? yesterday


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