I recently attempted to install a fresh CentOS on a pair of recycled (previously used in a different linux sistem) hard disks.
Of course I got the classical message that the disks already had RAID metadata on them:
“Disk contains BIOS metadata, but is not part of any recognized BIOS RAID sets. Ignoring disk sda”
Same for sdb.
To fix this so the installation lets us use the disks, we need to boot to some kind of linux console (I prefer SystemRescueCD), and type in:
dmraid -r -E /dev/sda
Replace sda with the disks on your computer (can be hdX or hdX, with X being any letter, depending on the port they are connected to and the order)
To find out all attached/available disks names, use