Re: kernel 2.4.0 + software RAID causes problems

[Neil Brown]

On Sunday January 7, [e-mail] wrote:
> Hi,
> 
> on my machine (x86) I've debian2.2r2 with kernel 2.2.16 + raidtools 0.9
> running. No problems. Yesterday I installed kern 2.4.0 with the same
> configuration like 2.2.16. I added following to the boot params:
> 
> root=/dev/md0 md=0,/dev/hde1,/dev/hdg1
> 
> If I boot 2.4.0 I can see following:
> 
> ...
> <init of raid>
> raid:0 md-size is 249728 blocks
> raid0: conf->smallest->size is 249728 blocks
> raid0: nb_zone is 1
> raid0: blocking 8 bytes for hash
> md: updating md0 RAID superblock on device                <<<------
> <...>
> ... autorun DONE
> md: loading md0
> ... md0 already autodetected -use raid=noautodetect
> <...>
> Parallelizing fsck version 1.18
> fsck.ext2: No such file or directory while trying to open /dev/md0 (null):
> The superblock could not be read or does not describe a correct ext2
> filesystem.
> 
> 
> The filessystem is clean because I can mount it with kernel 2.2.16 without
> problems. Maybe kernel 2.4.0 does the wrong in updating the RAIS superblock
> on md0.
> Please help!
> 

My guess - based on incomplete info - is that you have compiled in
devfs and told it to automount /dev.
If this could be the case, try booting with the extra option:

   devfs=nomount

The problem would be that /etc/fstab expects to find /dev/md0, but
devfs only provides /dev/md/0 - until devfsd is running, which
presumbly isn't until after fsck completes.

If that isn't the case I need more detail:

1/ I assume that your root filesystem is a raid0 array of /dev/hde1
   and /dev/hdg1.   Is that correct?
2/ What happens when you add the "raid=noautodetect" boot option as
   suggested in the log?
3/ What happens if you boot *without* the md=0,.... option?

NeilBrown

> with regards,
> Oliver
> 
> 
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