When using RAID arrays and changing their configuration, in some cases, the disks may not be recognized during the system reinstallation. In such situations, formatting the disks with standard tools does not help because RAID array metadata remains on the drives. To resolve this issue, you need to remove these RAID array labels. You can do this using the command-line utility mdadm, which is available in most Linux systems. First, you need to boot from a live image of a Linux-based operating system and open a terminal.
First, stop the RAID array:
mdadm –stop /dev/mdX
(mdX is the device name in your system, and the number may vary).
You can identify it using the command:
mdadm -A –scan
or
mdadm –detail /dev/mdX
Erase the superblock on each disk in the array:
mdadm –zero-superblock /dev/sdaX
mdadm –zero-superblock /dev/sdbX
After that, run:
mdadm –remove /dev/mdX
If the Live OS mounts the array in the system, you’ll need to unmount it before removing the array itself:
umount -l /dev/md0
