Re: Debian + LVM + RAID1
Damon L. Chesser wrote:
> Ivan Glushkov wrote:
>> Damon L. Chesser wrote:
>>
>>> snip
>>>
>>>> I taught I have to install the grub on the raid array, thus the grub
>>>> will put a copy of itself on the first partition on both hard drives,
>>>> used for the raid1, right?
>>>>
>>> Wrong AFAIK. You can do that IF you have a boot loader on the MBR
>>> pointing to grub.
>>>
>>
>> Now I am confused. Isn't grub a boot loader? Why would I need another
>> boot loader pointing to grub? I want to put grub on the MBR of both hard
>> drives from which my raid1 array consist of.
>>
>> BIOS does not read software raid and knows nothing
>>
>>> about software raid.
>>>
>>
>> Indeed, but I do not expect from the bios to read my raid array. I
>> merely want it to look for boot record in the MBR of one of the two hard
>> drives on which I have my raid arrays.
>>
>> Software raid does not come into play until the
>>
>>> kernel via initrd is loaded. Install to the MBR of the first HD of the
>>> array, then use grub to install into the MBR of the other members.
>>>
>>
>> What I meant with the paragraph you are referring to is exactly that:
>> issuing:
>>
>> grub-install /dev/md0
>>
>> should install (as fas as I understand it) a copy of grub in each hdd
>> from which the raid1 consist of (note: the partitions from both hard
>> drives included in md0 are both 512 MB and starting from the beginning
>> of the hard drives).
>>
>
> Truly, I don't know if you install grub onto a raid1 if it will install
> it onto the MBR of both physical HDs. I just always made partitions for
> the /boot, installed to one, moved the data around and made a mdX out of
> it and installed grub onto the other member. Re-inventing the wheel?
> Probably.
>> If I
>>
>>> am wrong, then it is news to me, but hey, I will learn new things! See
>>> my old "howto" on Linux, grub and raid at damtek.com for the exact
>>> commands. It is not pretty, but it will work.
>>>
>>
>> I tried that. Thanks.
>>
>> Basically the problem was easily solved. I had to tag both partitions to
>> be used for my /boot raid1 array as primary and bootable (stupid of me,
>> I know). But there is now another problem:
>>
>> I see already the grub initial screen, but when I hit enter, I get the
>> following:
>>
>> Booting 'Debian GNU/Linux, kernel 2.6.24-1-amd64'
>>
>> root (hd5,0)
>> Filesystem type unknown, partition type 0x7
>> kernel //vmlinuz-2.6.24-1-amd64 root=/dev/mapper/vg00-root ro linux26
>> quiet
>>
>> Error 17: Cannot mount selected partition
>>
>> Press any key to continue...
>>
>> I suppose grub does not know anything about LVM and the partitions on
>> that. If I am right, I have to rebuild initrd, right? But how do I tell
>> it to enable the lvm?
>>
>
> You have me there, it should have done it automagicaly when it
> installed. Use rescue mode, but I am not sure what command you should
> use to re-generate it. Perhaps chroot to your /, then try to run mkinitrd.
>
> do you have a line in grub like this?
>
> title Debian GNU/Linux, kernel 2.6.25-1-amd64
> root (hd0,5)
> kernel /boot/vmlinuz-2.6.25-1-amd64 root=/dev/hda6 ro quiet
> ------->>>>>>> initrd /boot/initrd.img-2.6.25-1-amd64
> <<<<<<<<<<<-------
I have this line in /boot/grub/menu.lst
I tried in the following sequence to:
0. boot resque
1. mount /boot from raid1 and the other directories from the lvm volumes
1. enter lvm into /etc/modules,
2. rebuild initrd with:
mkinitramfs -o /boot/grub/initrd.img-2.6.24-1-amd64
3. install grub into the MBR of both disk with
grub-install /dev/sdc
grub-install /dev/sdd
but still the same message appears when I try to boot :(
How can I check if the lvm support is really seen by grub?
I find this (http://grub.enbug.org/LVMandRAID) article claiming that I
have to enter "insmod lvm" in a file named grub.cfg. But I don't have a
file like this in my system?!
>
> If not, that would seem to mean you don't have an intrd.
>
>
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