[CentOS] Centos 7 and Software Raid Minimal Install

Wed Jun 1 17:25:17 UTC 2016
Matt <matt.mailinglists at gmail.com>

I am trying to install Centos 7 on a couple 4TB drives with software
raid.  In the Supermicro bios I set UEFI/BIOS boot mode to legacy.  I
am using the Centos 7 minimal install ISO flashed to a USB thumb

So I do custom drive layout something like this using sda and sdb.

Create /boot as 512 MB XFS raid1 array.

Create SWAP as 32 GB SWAP raid1 array.

Create / on 3.xxx TB XFS raid1 array.

I then get error.

"Your BIOS-based system needs a special partition to boot from a GPT
disk label.  To countinue, please create a 1MiB 'biosboot' type

I cannot seem to create the biosboot partition so it is mirrored to
both drives for redundancy.  Any ideas how to do this?  I want
everything mirrored to both drives.