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

[Pete Biggs]

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.

P.