[CentOS] Install Questions

Sun Dec 29 20:52:47 UTC 2019
Eugene Poole <etpoole60 at comcast.net>

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