Re: GRUB2, GPT, mdadm & LVM

[Andrey Borzenkov]

В Thu, 18 Jul 2013 14:38:46 -0600
Chris Murphy <address@hidden> пишет:

> 
> On Jul 18, 2013, at 12:50 PM, Sander Smeenk <address@hidden> wrote:
> 
> ---alot more snipped---
> > + partmap_module= part_gpt part_gpt part_gpt part_gpt part_gpt part_gpt 
> > part_gpt part_gpt part_gpt part_gpt part_gpt part_gpt part_gpt part_gpt 
> > part_gpt part_gpt
> 
> 
> Seems like a lot of instances of part_gpt. And then I see:
> 
> > 
> > /usr/sbin/grub-bios-setup: info: Inserting hostdisk//dev/sdp into md/0 
> > (mdraid1x)
> 
> 
> /dev/sda through /dev/sdp are inserted into md/0 by grub-bios-setup. That's 
> at 11 disk RAID 6? I defer to Andrey if that's even supportable. 
> 

grub2 does not have any artificial limits, so as long as it works with
Linux MD, it should work with grub.

> In GRUB rescue, does it list all 11 drives with the ls command? I wonder if 
> md0 is invalid, despite being listed.

Yes. MD array will appear in the list as soon as at least one member
was seen, but we need enough members so it becomes ready and can be
scanned for LVM. May be extending ls so it can show diskfilter volume
states would be useful.

So the first think to check is how many physical disks are visible at
grub prompt.

> Or if it's short one or two drives and in effect is
> degraded. I think this is an extremely fragile arrangement. You're
> better off with /boot on a 2 or 3 disk RAID1, and duplicate GRUB
>core.img in each of their BIOS boot partitions.
>