Zyxel NAS Server hard drive data recovery

Question

I had a Zyxel NSA-325v2 NAS Server, however the server failed and I cannot connect to it anymore and now I am trying to recover the data, however I have no idea which disk format it used.

Windows diskpart cannot detect the drive (marked as Disk 4):

    DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online         3726 GB  1024 KB        *
  Disk 4    Online             0 B      0 B

I tried several other tools but non could detect anything:

Aomei disk partition tool:

Reclaime:

Is there any way how to safely recover or browse the data on the harddrive so I can copy all data to a new NAS server ?

Answer 1

Solved by connecting 1 of the drives from raid 1 to Linux PC:

apt-get update
apt-get install mdadm

mdadm --assemble --scan

mkdir /mnt/raid
mount /dev/md/0 /mnt/raid