This is my situation: I've a AMD Phenom II X6 1055T machine with 2 - ISA DVD drives and 6 - SATA Drives.? The drives are (I assume by the BIOS) assigned /dev/ sda through /dev/sdf. In order to do a specific definition easily I use CentOS 6 (what disks are used with RAID-1 and which ones are used with RAID-10) and what the /dev/mdx names to use. What I don't understand is why when I get to the page where I'm to install the boot loader it wants to install it on /dev/sdf. When I try to install it on /dev/md0 (where /boot is located) the reboot fails. When I try to alter the BIOS order (it allows me to do this with 4 of the 6 disks) so the /dev/sda is the first BIOS drive the also fails. Before I had multiple disks in a RAID environment I could install the boot loader on /dev/sda1 without problems (BTW, /dev/md0 is defined with /dev/sda1 and /dev/sdd1). What am I doing wrong and how can I make it better? BTW, My goal is to get the file system defined exactly like I want it and then install CentOS 7.5 (CentOS 7.7 gives me several warning messages concerning my processor). TIA -- Eugene Poole Woodstock, Georgia