[GLLUG] problem with grub

[Paul Hewlett]

I have never done this so YMMV...

It appears that Grub does not do raid1 but the way round this is to specify
one of the 2 /boot partitions as a normal device.

if /dev/md0 consists of /dev/sda1 and /dev/sdb1 then specify either
/dev/sda1 or /dev/sdb1 as the boot partition.

It is also a good idea to put a fallback entry in grub to boot of the other
partition in case of error.


The other cause of error may be that your initramfs is not loading the
dmraid kernel module so check that as well.


This link may help you...

http://www.howtoforge.com/software-raid1-grub-boot-debian-etch-p2


Paul


On 14 Mar 2014 20:14, "Ben Whyall" <ben at whyall-systems.co.uk> wrote:

> Hi
>
> How do I get a list of uuid from grub command line.
>
> I have tried setting root=/dev/md0 which is where the /boot is but that
> just sits at loading initial ramdisk .... and doesnt seem to do anything.
>
> Ben
>
>
>
> On 14/03/14 10:46, Mike Brodbelt wrote:
>
>> It sounds to me from your description that grub is attempting to use the
>> wrong disk. You say the uuid it appears to be trying to find the kernel on
>> is in fact the uuid of one of your LVM volumes. I suspect all you need to
>> do is enumerate the disks visible to the grub shell, and point it at the
>> uuid of your actual /boot partition, in order to boot successfully. You'll
>> then need to correct the grub config. Be aware that the grub "root" is the
>> device where it expects to find the kernel (i.e. /boot) and not your root
>> filesystem.
>>
>> Mike
>>
>> On 14 March 2014 09:12:18 GMT+00:00, Ben Whyall <ben at whyall-systems.co.uk>
>> wrote:
>>
>>> On 14/03/2014 09:05, Chris Bell wrote:
>>>
>>>> On Fri 14 Mar, Ben Whyall wrote:
>>>>
>>>>  Hi
>>>>>
>>>>> Its Debian unstable not recently installed but possibly the first
>>>>>
>>>> time
>>>
>>>> its been rebooted since kernel upgrade.  Although none of the old
>>>>> kernels boot either.
>>>>>
>>>>> Interestingly when you look at the blkid that uuid exists its one of
>>>>>
>>>> the
>>>
>>>> inactive lvm logical volumes.
>>>>>
>>>>> Ben
>>>>>
>>>>>
>>>>      Have you tried updating grub?
>>>>      Not sure whether this is relevant. There has been some frenzied
>>>>
>>> activity
>>>
>>>> relating to Debian Testing and Unstable because even the installer
>>>>
>>> discs
>>>
>>>> have given problems. It seems that in an attempt to check other
>>>>
>>> possible
>>>
>>>> locations the correct location is sometimes missed and/or there is a
>>>>
>>> hang.
>>>
>>>>
>>>>
>>> Hi
>>>
>>> I have tried updating grub but not managed to get it to run
>>> successfully.  I have not managed to get to a point where I have the
>>> boot partition and enough of the lvm partitions available to be able to
>>>
>>> update grub.
>>>
>>> How would I go about getting to a point where I can run the update-grub
>>>
>>> with the relevant file systems up ?
>>>
>>> Ben
>>>
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>>>
>>
>>
>
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