[CentOS] CentOS 7 install on one RAID 1 [not-so-SOLVED]

Wed Jan 25 11:06:17 UTC 2017
Pete Biggs <pete at biggs.org.uk>

On Tue, 2017-01-24 at 17:14 -0500, m.roth at 5-cent.us wrote:
> So, it installed happily.
> Then wouldn't boot. No problem, I'll bring it up with pxe, then chroot and
> grub2-install.
> Um, nope. I edited the device map from hd0 and hd1 being the RAID to
> /dev/sda and /dev/sdb, then ran grup2-install. It now tells me can't
> identify the filesystem on hd0, and can't perform a safety check, and
> gives up.
> What am I missing? Google is not giving me any answers....

Surely, if you are using software RAID, then you should configure that
RAID in anaconda, that will then cope with setting up the partitions to
allow booting.  Basically it needs a small non-RAID partition to hold
/boot on the boot disk.

Remember that the boot sequence is generally: BIOS reads MBR and
executes it; MBR code reads kernel from /boot and executes it (yes,
it's more complicated than that). If the MBR code doesn't know how to
read a RAID partition, then it's going to fail, that's why you have a
small non-RAID partition to hold /boot.

Hardware RAID is different because it interfaces at the BIOS level so
the MBR code doesn't need to know how to specifically read it.