Re: BIOS Boot partition
On Mon, Jul 18, 2016 at 5:18 PM, Samuel Sieb <samuel(a)sieb.net> wrote:
On 07/18/2016 01:07 PM, Chris Murphy wrote:
>
> On Mon, Jul 18, 2016, 1:40 PM Samuel Sieb <samuel(a)sieb.net
> <mailto:samuel@sieb.net>> wrote:
> Since you are creating a bios boot partition, you must be using the
> non-GPT partition table.
>
> BIOS Boot is where the core.img is embedded when using GPT partitioning
> with BIOS firmware.
>
Sorry about that, that is one combination I have not had any reason to use,
so I didn't recognize it.
However, I would still suggest doing RAID over the entire drive instead of
partition by partition because that would solve this entire issue. You
wouldn't have to worry about getting grub installed on the second drive or
dealing with creating extra partitions.
I don't think that's a supported configuration. For sure it's not a
layout the installer will create. It's probably a violation of the
UEFI spec, except when the firmware itself understands the on-disk
RAID format and can assemble the RAID in the pre-boot environment.
Otherwise you end up with this big fat lie: The member drives are in
fact RAID members first, and should not be individually recognizable;
but by putting the RAID metadata at the end of the disk so that it
doesn't conflict with the partition scheme, member drives are seen as
individuals as if they aren't RAID members, hence the lie, and can in
fact become inconsistent should any of those partitions be mounted and
modified prior to RAID assembly.
The only really safe ways to do this? Firmware assembled RAID, or
conventional partitioning with either LVM RAID or mdadm metadata
version 1.2 (the default). This prevents the individual member devices
from being recognized prior to RAID assembly.
I think Fedora 25 will bring a new feature to the installer that
supports LVM RAID, which makes things a lot more flexible in the
direction you're suggesting. Every device has a conventional partition
scheme, each gets a bootloader (this is totally broken on UEFI right
now still), and an mdadm v 1.2 partition for /boot, and then the
largest partition is LVM. From that large LVM pool, each LV can have
its own RAID level from 0 through 6. So you don't have to mess around
with disk partitioning (MBR or GPT) to create different levels of RAID
from that pool, and they can be mixed and matched.
--
Chris Murphy