[ale] Problems with Debian 5.0 linux-image grub run on software RAID

[Chris Woodfield]

Right - that's exactly the setup I have - you wind up "tricking" grub  
to treat the RAID 1 /boot partition as a regular partition. However,  
looks like Lenny's linux-image postinstall scripts have wised up to  
the subterfuge, for no good reason...

-C

On Mar 18, 2009, at 12:38 AM, Chris Kleeschulte wrote:

> Hi Chris:
>
>
> Yes, you are correct...grub does know about filesystems but not RAID,
> so RAID1 is used for boot partitions since it is mirrored. I have a
> debian etch machine running the boot partition off a RAID1 device. I
> simply pointed the my root device to (hd0,0) (in my case). Please
> excuse me if this is too trivial help you, but seems like it might
> help. I am using software RAID1 with LVM on that. If I missed
> something let me know.
>
> The above could be brittle if hd0 fails, but you can operate still,
> but rebooting without changing your root will be an issue.
>
>
> Chris
>
>
> Chris Kleeschulte
>
>
> On Mar 16, 2009, at 12:09 PM, Chris Woodfield wrote:
>
>> Hi all,
>>
>> I posted the below to forums.debian.org but got no response; maybe
>> someone here might have an idea what's going on? Long story short,  
>> the
>> linux-image postinst script in Debian 5.0 (Lenny) breaks when /boot  
>> is
>> a RAID 1 partition.
>>
>> Basically, grub doesn't grok RAID directly, but since each disk in a
>> RAID 1 array is identical to what would live on a single non-RAID
>> disk, you could set up the array and  just point grub to the physical
>> partition. Once grub is done, the kernel mounts /boot as RAID 1, and
>> everything is good. However, the update-grub postinst script in Lenny
>> now tries to look up /boot's mount point and verify that it's the  
>> same
>> partition that appears in device.map, (which it isn't).
>>
>> Below is my post:
>>
>> http://forums.debian.net/viewtopic.php?t=37095
>>
>> And the error generated by the update-grub postinst script is:
>>
>> Running postinst hook script /usr/sbin/update-grub.
>> Searching for GRUB installation directory ... found: /boot/grub
>> warning: grub-probe can't find drive for /dev/evms/md/md0.
>> error: array->nr_devs > array->total_devs (3)?!?
>> grub-probe: error: Cannot find a GRUB drive for /dev/evms/md/md0.
>> Check your device.map.
>>
>> Originally I had /boot mounted from /dev/md0 - suspecting the evms
>> might be the issue, I changed this to mount at /dev/evms/md/md0, but
>> that did not solve the problem.
>>
>> Thanks in advance!
>>
>> -Chris
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