Re: does grub understand LVM raid1 layouts?

[Andrei Borzenkov <arvidjaar@gmail.com>]

В Thu, 28 Aug 2014 14:31:30 +0100
Bayard Bell <buffer.g.overflow@gmail.com> пишет:

> In moving my boot device to mirrored LVM under Debian jessie, I ended up
> unable to boot. I thought my problem was that I failed to run install-grub
> after adding GRUB_PRELOAD_MODULES=lvm to /etc/default/grub, but when I
> finally sorted out a working PXE image for rescue, I found that I was
> unable to install while mirrored. That appears to be in part because Debian
> has taken upgrades to LVM2 that change the default mirroring layout from
> "mirror" to "raid1" (mirror_segtype_default = "raid1" in /etc/lvm/lvm.conf;
> the lvm pages are also clear on this distinction and the defaults), which
> results in an inability to successfully probe /boot/grub, which breaks
> grub-install. The clearest indication I could find of this as likely root
> cause was a debug message from grub-probe "Unknown LVM format raid1".
> Looking at the source head, it appears that there's first a check for raidX
> in lines 580-583 of grub-core/disk/lvm.c but that the subsequent switch at
> lines 587-600 provides for raid[456] but not raid1, which isn't defined in
> include/grub/diskfilter.h.
> 

Is there functional difference (to the extent grub is using it) between
mirror and raid1 in LVM? If not, just use GRUB_DISKFILTER_MIRROR in
this case.

> I'm looking at doing a bit more debug to confirm this before assessing fix
> options, but am I on the right track thus far?
> 

Yes. Patch is appreciated.