I built a RAID5 array with 4 2Tb devices a few month ago.
- I used LVM2 to build partitions.
- I also used GRUB2.
- Finally I installed Debian.
For an unknown reason the RAID failed.
The BIOS "see" ...
I have a RAID5 array consisting of 3 identical 2TB drives. Suddenly GRUB wouldn't boot anymore and gave the error out of disk.
Eventually booted a livecd and ran some mdadm commands:
mdadm --examine ...