[ale] Converting to RAID5 root

[Chris Woodfield]

Problem solved...I had neglected to create /dev or /proc directories  
in my new root, preventing those filesystems from being mounted.  
Lessons learned, yadda yadda.

Thanks for the replies,

-C

On Mar 5, 2006, at 11:17 AM, Chris Woodfield wrote:

> Yeah, I realized I wrote this in a bit of haste. Let me explain the
> setup more clearly:
>
> I initially installed my linux distro on a regular ATA drive,
> standard debian 3.0 defaults (root at /dev/hda1, /home on /dev/hda5).
>
> I then added three SATA drives to the system, with the intent of
> migrating the system over to the raid array. GRUB sees these as (hd2)
> through (hd4). The libata driver names then /dev/sda - /dev/sdc.
>
> I set up the following arrays on the three drives:
>
> md0 - sda1, sdb2 - RAID 1 array to load kernel, will mount as /boot.
> md1 - sda5, sdb5, sdc5 - RAID5 array to mount as /
> md2 - sda6, sdb6, sdc6 - RAID5 array hosting LVM partitions
>
> I solved the kernel panic issue already - I had incorrectly assumed
> that the initrd image generated by make-kpkg would load the proper
> SATA modules and autodetect my SATA drives. It didn't. So I commented
> the initrd out of menu.lst, compiled libata and RAID support into the
> kernel directly, and rebooted.
>
> The system now autodetects the arrays, and mounts /dev/md1 as the
> root partition, but then bombs with this error immediately after
> mounting /dev/md1 :
>
> "Warning: could not open inital console"
>
> And I'm clueless, again.
>
> Any ideas on that one?
>
> -C
>
> On Mar 5, 2006, at 9:26 AM, H. A. Story wrote:
>
>> This defies my logic of RAIDS.   Is this a software RAID?  A RAID 1
>> requires at least 2 drives.  A RAID 5 requires at least 3 drives.   
>> You
>> don't appear to have enough.  You would need a total of 5 drives for
>> this configuration.  Unless you were doing sometime of magic with
>> software RAID.  And that some how doesn't sound like a good idea.
>>
>> However if I am wrong I was reading something the other day about
>> initrd.  This would have to be loaded before attempting to mount the
>> root.  I THINK.  It needs to load the drivers for the RAID before the
>> kernel can boot.
>>
>> Chris Woodfield wrote:
>>
>>> OK, here goes...
>>>
>>> I'm converting a standard one-drive debian sid installation to a 3-
>>> drive RAID. I current have both the original drive and the three  
>>> SATA
>>> drives installed in the system. I've maid the raid partitions  
>>> with no
>>> issues. I have three RAID partitions:
>>>
>>> md0	boot partition, RAID 1
>>> md1	root, RAID 5
>>> md2 	LVM volume, RAID 5
>>>
>>> What I'm trying to do at the moment is make sure I can boot off of
>>> the RAID set with md1 as the root partition. Here's the relevant  
>>> part
>>> of menu.lst on the primary drive:
>>>
>>> title           Debian GNU/Linux, kernel 2.6.15.4 RAID
>>> root            (hd2,0)
>>> kernel          (hd2,0)/vmlinuz-2.6.15.4 root=/dev/md1 ro
>>> initrd          (hd2,0)/initrd.img-2.6.15.4
>>> savedefault
>>> boot
>>>
>>> title           Debian GNU/Linux, kernel 2.6.15.4 RAID (recovery
>>> mode)
>>> root            (hd2,0)
>>> kernel          (hd2,0)/vmlinuz-2.6.15.4 root=/dev/md1 ro single
>>> initrd          (hd2,0)/initrd.img-2.6.15.4
>>> savedefault
>>> boot
>>>
>>> I've already copied all the filesystems over to the relevant RAID
>>> partitions. RAID is compiled into the kernel.
>>>
>>> By all appearances, GRUB is able to boot the kernel that lives on  
>>> the
>>> md0 volume, but I get a kernel panic at the point where the system
>>> attempts to mount /dev/md1 as the root volume. The error reads:
>>>
>>> VFS: Cannot open root device "md1" or unknown-block(0,0)
>>> Please append a correct "root=" option
>>> Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-
>>> block(0,0)
>>>
>>> Is there something that needs to be set up prior to this mount
>>> operation (a boot arg, for example) such that the kernel knows  
>>> how to
>>> assemble /dev/md1? Is this something that should be in the initrd
>>> that make-kpkg creates? Any other ideas?
>>>
>>> Thanks,
>>>
>>> -Chris
>>>
>>> _______________________________________________
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>>> Ale at ale.org
>>> http://www.ale.org/mailman/listinfo/ale
>>>
>>>
>>>
>>
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