When trying to install CentOS or Red Hat Linux, you may come upon this error message – “Disks sda, sdb contains BIOS RAID metadata, but are not part of any recognized BIOS RAID sets. Ignoring disks sda, sdb”. This may be due to an existing or previously existing RAID configuration typically found in on-board RAID and configured in the BIOS.
1. Restart your system.
2. Go into your BIOS Setup and make sure your SATA type is set to AHCI and not RAID.
3. Boot into CentOS or Red Hat “Rescue Mode” from your boot media.
4. Enter into the shell.
5. Type the following commands:
dmraid -r -E /dev/sda
dmraid -r -E /dev/sdb