Re: [gentoo-user] Grub2 boot problem

[Magnus Johansson]

> you need to include the punctuation, specifically the ":"s, which usually
> are a "-", mac addresses use the ":" but unless the syntax has
> changed/broadened you have to have the "-" for seperating the fields in a
> uuid.  The punctuation is  part of the syntax (besides breaking the uuid
> into sections which makes it easier to copy/verify).   for data overload see
>  and the
> associated links.

So what should I change and where? I seem to get three different
formats depending on source:

m ~ # blkid
/dev/md127: UUID="cd3438aa-c02b-4d03-8085-596a8d60b7c2" TYPE="ext4"
/dev/sdb4: UUID="533875eb-d678-7e77-285b-41ab6c964566"
UUID_SUB="1f217f50-3b45-921c-629c-7e5df708964f" LABEL="livecd:2"
TYPE="linux_raid_member" PARTLABEL="root"
PARTUUID="a2ae84d5-1ede-428e-9beb-816ea57bfa05"
/dev/md125: UUID="6fd35ea8-dc72-46ac-b009-e722ca3d5487" TYPE="ext2"
/dev/sdb2: UUID="46488b25-9685-a3b9-c52b-7449d592dc80"
UUID_SUB="25f34072-d83d-2a6c-0e3f-7d6df5161b1b" LABEL="livecd:0"
TYPE="linux_raid_member" PARTLABEL="boot"
PARTUUID="91c5c25d-4742-4e7e-b1b9-4f759c359e90"
/dev/md126: UUID="fdecc9e5-e411-4d32-a591-ee03850bb538" TYPE="swap"
/dev/sdb3: UUID="04b7f579-0264-ee93-dc84-276121816571"
UUID_SUB="dc306764-79d7-b606-058e-d855f59f2757" LABEL="livecd:1"
TYPE="linux_raid_member" PARTLABEL="swap"
PARTUUID="988650cb-dbc0-4b2b-a314-959f18537bd6"
/dev/sda2: UUID="46488b25-9685-a3b9-c52b-7449d592dc80"
UUID_SUB="ab474afa-d46a-4bbc-31fd-735cdb95673c" LABEL="livecd:0"
TYPE="linux_raid_member" PARTLABEL="boot"
PARTUUID="46916efb-ef91-45ce-8aa8-c2cee33b980f"
/dev/sda3: UUID="04b7f579-0264-ee93-dc84-276121816571"
UUID_SUB="ec6eca1f-26e9-b328-642a-884643c9df48" LABEL="livecd:1"
TYPE="linux_raid_member" PARTLABEL="swap"
PARTUUID="9fb247a0-3eaf-4bc2-a58b-117c9f662355"
/dev/sda4: UUID="533875eb-d678-7e77-285b-41ab6c964566"
UUID_SUB="54b01e83-bbc4-4fb4-7f6f-1c3dcb7c198b" LABEL="livecd:2"
TYPE="linux_raid_member" PARTLABEL="root"
PARTUUID="b10527b2-a782-478a-aaf5-a2fc268bdb5d"
/dev/sdb1: PARTLABEL="grub" PARTUUID="54981880-24b5-4194-b0a7-049f575861b4"
/dev/sda1: PARTLABEL="grub" PARTUUID="a7ec1c8e-688f-43ed-8597-04717e93ce8d"
m ~ # grub-probe -t drive -d /dev/md125
(mduuid/46488b259685a3b9c52b7449d592dc80)
m ~ # mdadm -D /dev/md125 | grep UUID
   UUID : 46488b25:9685a3b9:c52b7449:d592dc80
m ~ #

Re: [gentoo-user] Grub2 boot problem

[Magnus Johansson]

 I've got a fresh Gentoo installation that does not boot. I just end up in
 the Grub2 shell.

 However when there if I do 'set root=(md/0)' and 'configfile 
 /grub/grub.cfg'
 I do get to the Grub2 menu where Gentoo boots just fine.

 /boot and / are both on mdadm devices.

 I've tried re-running grub-mkconfig and grub-install several times without
 luck.

 I've added domdadm to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub.

 Drives sda/sdb use GPT disklabels and have 20M BIOS boot partitions first.
>>>
>>> To which device are you installing grub?
>>>
>>> Check what "core.img" prefix and modules grub-install is using with
>>>
>>> grub-install --debug $your_device 2>&1 | grep grub-mkimage
>>>
>>> [I hit a similar problem with mdadm 6 or 7 years ago and had to create
>>> a custom "core.img" to boot normally. You might have to do the same
>>> but i would've thought that this problem's been solved. I haven't
>>> encountered it since.]
>>
>> I install grub to devices sda and sdb in the hope I can boot from both/either
>>
>> m / # grub-install --debug /dev/sda 2>&1 | grep grub-mkimage
>> grub-install: info: grub-mkimage --directory '/usr/lib/grub/i386-pc'
>> --prefix '(mduuid/46488b259685a3b9c52b7449d592dc80)/grub' --output
>> '/boot/grub/i386-pc/core.img' --format 'i386-pc' --compression 'auto'
>> 'ext2' 'part_gpt' 'part_gpt' 'diskfilter' 'mdraid1x' 'biosdisk'
>> m / #
>
> [ I assume that "46488b259685a3b9c52b7449d592dc80" is the UUID that's
> displayed as "UUID" or "Array UUID" when you use "mdadm -D ..." or
> "mdadm -E ..." respectively ]

Almost, mdadm says 46488b25:9685a3b9:c52b7449:d592dc80

> Does "set" in the grub shell display
> "prefix=(mduuid/46488b259685a3b9c52b7449d592dc80)/grub" and
> "root=(mduuid/46488b259685a3b9c52b7449d592dc80)"?

Yes, I messed up the prefix=-line when retyping it.

> Does "grub-probe -t drive -d /dev/md0" output "(mduuid/...)" or
> "(md/0)" or "(md0)"?

It ouputs "(mduuid/46488b259685a3b9c52b7449d592dc80)"

Re: [gentoo-user] Grub2 boot problem

[Magnus Johansson]

2018-02-07 18:50 GMT+01:00 Steven Lembark <lemb...@wrkhors.com>:
> On Mon, 5 Feb 2018 22:00:39 +0100
> Magnus Johansson <gen...@rnd.se> wrote:
>
> From my grub.cfg:
>
> insmod gzio
> insmod part_msdos
> insmod diskfilter
> insmod mdraid1x
> insmod raid5rec
> insmod lvm
> insmod xfs
>
> Sanity check that you have all of the necessary modules installed
> (e.g., "mdraid*" "raid5rec").

How do you mean? Since 'set root' and 'configfile' makes it boot I'd
assume the modules are there?

I ran 'set' from grub2 shell and

cmdpath=(hd0)
prefix=(mduuid/)/root=grub
root=mduuid/

Where  is the correct UUID.

Which looks ok?

Re: [gentoo-user] Grub2 boot problem

[Magnus Johansson]

> > I've got a fresh Gentoo installation that does not boot. I just end up in
> > the Grub2 shell.
> >
> > However when there if I do 'set root=(md/0)' and 'configfile /grub/grub.cfg'
> > I do get to the Grub2 menu where Gentoo boots just fine.
> >
> > /boot and / are both on mdadm devices.
> >
> > I've tried re-running grub-mkconfig and grub-install several times without
> > luck.
> >
> > I've added domdadm to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub.
> >
> > Drives sda/sdb use GPT disklabels and have 20M BIOS boot partitions first.
>
> To which device are you installing grub?
>
> Check what "core.img" prefix and modules grub-install is using with
>
> grub-install --debug $your_device 2>&1 | grep grub-mkimage
>
> [I hit a similar problem with mdadm 6 or 7 years ago and had to create
> a custom "core.img" to boot normally. You might have to do the same
> but i would've thought that this problem's been solved. I haven't
> encountered it since.]

I install grub to devices sda and sdb in the hope I can boot from both/either

m / # grub-install --debug /dev/sda 2>&1 | grep grub-mkimage
grub-install: info: grub-mkimage --directory '/usr/lib/grub/i386-pc'
--prefix '(mduuid/46488b259685a3b9c52b7449d592dc80)/grub' --output
'/boot/grub/i386-pc/core.img' --format 'i386-pc' --compression 'auto'
'ext2' 'part_gpt' 'part_gpt' 'diskfilter' 'mdraid1x' 'biosdisk'
m / #

[gentoo-user] Grub2 boot problem

[Magnus Johansson]

Hello.

I've got a fresh Gentoo installation that does not boot. I just end up in
the Grub2 shell.

However when there if I do 'set root=(md/0)' and 'configfile
/grub/grub.cfg' I do get to the Grub2 menu where Gentoo boots just fine.

/boot and / are both on mdadm devices.

I've tried re-running grub-mkconfig and grub-install several times without
luck.

I've added domdadm to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub.

Drives sda/sdb use GPT disklabels and have 20M BIOS boot partitions first.

Thanks!