How to deal with RAID Metadata being apparently corrupted while hardware was transitioned?

Recently I tried migrating my HDDs (RAID5 – 4x 4TB) from an existing OMV6 setup to a fresh OMV8 installation on a new pc build, since the new motherboard offered me 2 more SATA slots.

Unfortunately the system had a problem with the SATA drives (very old motherboard primarily meant for IDE drives) and the system crashed while unlocking LUKS and mounting the storage pool.

This corrupted the metadata on 2 of the drives and the RAID was no longer recognized.

I moved the HDDs to another stable system and tried fixing the setup. Unfortunately after several days and going around in circles with ChatGPT (yeah I know, probably not the best idea) all i achived was rewriting the metadata once with mdadm --create --assume-clean and thus overwriting the superblocks on the 2 drives that previously where recognized as participants in the RAID. I have saved the metadata of the 2 drives before. I don’t know, if this potentially damaged the LUKS header.

So my current state:

  • No superblocks present.
  • No RAID metadata on the disks.
  • Data should be intact (because I used --assume-clean).
  • Drive order not known.
  • Drives present in stable system with OMV and Windows 10 installed.

What I know for sure:

  • Previous Structure: RAID5 with ext4 and LUKS.

  • RAID was created using OMV6 (including the LUKS add-on) (OMV installation is still intact and accessible).

  • Drive UUIDs don’t match the original ones in the old OMV config (new hardware).

  • Drive letters also scrambled.

  • LUKS password.

  • Data offset (from old raid metadata).

  • No physical disk failure.

  • Previous metadata of two drives:

    /dev/sdc:
              Magic : a92b4efc
            Version : 1.2
        Feature Map : 0x1
         Array UUID : c7902597:37b03a7f:65e30e58:c5ff5cd6
               Name : openmediavault:0  (local to host openmediavault)
      Creation Time : Thu Feb 1 14:59:35 2024
         Raid Level : raid5
       Raid Devices : 4
    
     Avail Dev Size : 7813772976 sectors (3.64 TiB 4.00 TB)
         Array Size : 11720658432 KiB (10.92 TiB 12.00 TB)
      Used Dev Size : 7813772288 sectors (3.64 TiB 4.00 TB)
        Data Offset : 264192 sectors
       Super Offset : 8 sectors
       Unused Space : before=264112 sectors, after=688 sectors
              State : clean
        Device UUID : 3b702221:b6bff32a:80c86da6:0f225da2
    
    Internal Bitmap : 8 sectors from superblock
        Update Time : Sun Feb 22 22:00:25 2026
      Bad Block Log : 512 entries available at offset 24 sectors
           Checksum : 731f3399 - correct
             Events : 23465
    
             Layout : left-symmetric
         Chunk Size : 512K
    
       Device Role : Active device 2
       Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
    
    /dev/sde:
              Magic : a92b4efc
            Version : 1.2
        Feature Map : 0x1
         Array UUID : c7902597:37b03a7f:65e30e58:c5ff5cd6
               Name : openmediavault:127  (local to host openmediavault)
      Creation Time : Thu Feb 1 14:59:35 2024
         Raid Level : raid5
       Raid Devices : 4
    
     Avail Dev Size : 7813772976 sectors (3.64 TiB 4.00 TB)
         Array Size : 11720658432 KiB (10.92 TiB 12.00 TB)
      Used Dev Size : 7813772288 sectors (3.64 TiB 4.00 TB)
        Data Offset : 264192 sectors
       Super Offset : 8 sectors
       Unused Space : before=264112 sectors, after=688 sectors
              State : clean
        Device UUID : 86f6a821:281889b3:ba2613bf:8b59b0a0
    
    Internal Bitmap : 8 sectors from superblock
        Update Time : Sun Feb 22 22:00:25 2026
      Bad Block Log : 512 entries available at offset 24 sectors
           Checksum : 1333a80b - correct
             Events : 23465
    
             Layout : left-symmetric
         Chunk Size : 512K
    
       Device Role : Active device 0
       Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
    

I really hope someone can advise me how to proceed here and potentially gain access to the filesystem again or at least the raw files.