Re: Problems probing a LVM device with GRUB2
On Fri, Sep 17, 2010 at 8:01 AM, Alberto Luaces <aluaces@udc.es> wrote:
> Tom H writes:
>> On Thu, Sep 16, 2010 at 6:02 AM, Alberto Luaces wrote:
> Hi Tom, thanks for the guidance, see below:
You're welcome. I'm sorry about the delay in responding. I screwed up
and archived a few threads by mistake (not for the first time it
seems!), of which this one.
>>> I'm trying to install GRUB2 to a disk that has an ext2/3 filesystem into
>>> a LVM partition. I can even start the system from GRUB2 and a boot disk,
>>> so it should work.
>>>
>>> The problem is that `grub-install' displays `no such disk' errors. I
>>> have tracked it down to `grub-probe':
>>>
>>> $ ls /dev/mapper/
>>> control lvm_volume-debian_root lvm_volume-swap
>>>
>>> $ sudo grub-probe -d /dev/mapper/lvm_volume-debian_root
>>> grub-probe: error: no such disk.
>>>
>>> How can I make `grub-probe' to find the partition? I'm using Squeeze,
>>> with latest GRUB2:
>>>
>>> $ dpkg -l grub-pc
>>> [...]
>>> ii grub-pc 1.98+20100804-4
>>
>> I have sid (with the same version of grub-pc) running with lvm.
I am assuming that you have a setuo like mine, where "/boot" isn't a
separate partition and /dev/sdb (I have /dev/sda but that shouldn't be
an issue) is your disk with one partition on which "/" in an lv.
>> What's the output of
>> cat /boot/grub/device.map
>
> $ cat /boot/grub/device.map
> (fd0) /dev/fd0
> (hd0) /dev/disk/by-id/ata-ST3320613AS_5SZ00HA9
Same for me and it's correct (as long as it corresponds to the
"/dev/disk/by-id/" entry of /dev/sdb).
>> grub-probe --target=abstraction /
>
> $ sudo grub-probe --target=abstraction /
> grub-probe: error: no such disk.
"The" problem.
I get "lvm".
>> grub-probe --target=device /
>
> $ sudo grub-probe --target=device /
> /dev/mapper/lvm_volume-debian_root
Same for me.
>> grub-probe --target=drive /
>
> $ sudo grub-probe --target=drive /
> (lvm_volume-debian_root)
Same for me.
> Thanks to that pointers of yours, I realized that I should update my
> device.map, adding a last line like this
>
> (lvm_volume-debian_root) /dev/mapper/lvm_volume-debian_root
>
> Now, I try to install grub again:
>
> $ sudo grub-install --no-floppy --modules="ext2 lvm" /dev/sdb
>
> The command finishes succesfully, but when I try to boot from my second
> hard disk (sdb), I get an error that looks like:
>
> error: no such device: ff5ef7a3-1d16-4a30-a3d5-1751c02c7630
> Entering rescue mode
>
> ff5ef7a3-1d16-4a30-a3d5-1751c02c7630 is the uuid of my /dev/dm-0. It
> seems now that the image of my grub doesn't have lvm support, even I
> activated it in the `grub-install' call.
>
> Any clue about this? Relevant snippet of my grub.cfg, note that there is
> no `insmod lvm' stanza!
>
> insmod ext2
> set root='(lvm_volume-debian_root)'
> search --no-floppy --fs-uuid --set ff5ef7a3-1d16-4a30-a3d5-1751c02c7630
Since grub-probe isn't detecting your lvm setup, it's normal for
grub.cfg not to have "insmod lvm".
I don't think that adding that adding that line to
"/boot/grub/device.map" could be that useful and I'm not sure that
whether adding "--modules=..." is additive or not because you need a
few more modules to be able to boot. I've forgotten the command to
list the core.img modules but I'll try to find it and list the default
ones that you'd have to add to your command if it isn't additive.
What is and what's on sda?
More data requests...
What is the output of:
pvs
lvs
vgs
fdisk -l /dev/sdb
grub-probe --target=drive -d /dev/sdb
grub-probe --target=drive -d /dev/sdbX
grub-probe --target=drive -d /dev/dm-0
grub-probe --target=drive -d /dev/mapper/lvm_volume-debian_root
(the last one with your extra line and with it commented out)
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