no root device found - can't boot [SOLVED]

[jankushka]

i see this on a friend's pc.
there's a raid controller on the motherboard (see details below).
raid is disabled in bios (standard sata access is set).
installer asks if i want to use it and i say "no".
i can partition the discs and installation is ok.
but i can't boot.
i get a "no root device found" message and the process drops to busybox.
as far as i can tell, the problem is in how initrd is built.
it seems it uses the raid no matter what (when i ctrl-alt-del i see a "stopping md..." something message).
using the old hardy initrd for the boot works ok.
i unpacked both the old and the new initrd and i see the new one has the raid stuff, while the old doesn't.
i see this since intrepid.

a fix is needed, i guess.

cheers

--
motherboard: ASUS P5WD2
RAID controller: Silicon Image 3132, Intel ICH7R Southbridge

[dibl]

Re: no root device found - can't boot

Did you try setting the "boot" flag on the root partition of that hard drive?

[jankushka]

Re: no root device found - can't boot

nope!
explain, please...

[Qqmike]

Re: no root device found - can't boot

Use GParted Live CD.
Boot it.
Highlight the partition (in the list) that your PC boots from.
Do you see a "boot" flag set on it (the word "boot" on the right end of that line)?
If not, then
Partition (tab at top) > Manage Flags, Check the "boot" box.
GParted > Quit, out, re-boot to test it.
(You have to double-click the large red Exit icon at the top of the GParted Desktop)

[jankushka]

Re: no root device found - can't boot

Use GParted Live CD.
Boot it.
Highlight the partition (in the list) that your PC boots from.
Do you see a "boot" flag set on it (the word "boot" on the right end of that line)?
If not, then
Partition (tab at top) > Manage Flags, Check the "boot" box.
GParted > Quit, out, re-boot to test it.
(You have to double-click the large red Exit icon at the top of the GParted Desktop)

thanks.
yes.
no.
i didn't mean that.
sorry.
my mistake.
i meant: please explain what's the rationale behind setting the boot flag on that partition.

cheers

[Qqmike]

Re: no root device found - can't boot

If I understand the question right ...

You set BIOS to boot from one of the hard drives.
So, BIOS looks at the MBR of that hard drive, it looks at the partition table in that MBR (= 4 partitions listed, each 16 bytes), and it looks for one of the four partitions (on that drive) to boot from as indicated by a boot flag set on that partition.

[jankushka]

Re: no root device found - can't boot

guess it's my fault again...

the system boots off the correct disc.
and it's not a grub error i get, either.
grub finds the device alright (hd0,4, in this case).
it starts the boot process alright.
it gets as far as "waiting for root file system" (which is when /usr/sbin/init should be started).
but the root file system in question (/dev/sda5) is not found.
at this point i get the "no root fs" message and i'm dropped to the busybox prompt.

if i use the old hardy initrd in my grub entry,
i can boot the very same jaunty installation from /dev/sda5
with no issues whatsoever.

[Qqmike]

Re: no root device found - can't boot

Puzzling that the old HH initrd works; you might guess the other way around (that HH GRUB initrd would not boot the newer OS, maybe because of the inode size issue we've seen here and there).

Well, anyway, I'll drop this in case you can make sense of it and use it to debug; never tried it myself (yet), but had it in my notes:


BusyBox—de-bugging/troubleshooting
BusyBox prompt
initramfs

when you boot, press esc when given the chance, then press 'e'. Edit the kernel line, remove "quiet splash" and add "debug". Then press enter and "b"
there should be a log under / or /tmp or /var/log (don't remember the path on top of my head)

file called "initramfs.debug"

Read using the commands "cat" or "more" and report any error. Errors will normally be at the bottom. You can scroll with shift+pgup

[jankushka]

Re: no root device found - can't boot

@Qqmike
thanks.
very useful.
will see if i can dig any useful info from busybox to understand exactly what happens.
unfortunately i won't have access to that friend's pc any time soon.
he's happy, anyway, 'cause my workaround with the old hh initrd allows him to boot jj, which he loves.

bye for now.
and thanks again.

cheers

[flarson]

Re: no root device found - can't boot

It sounds like root is using a filesystem that is supported in the older initer and not the newer. This just a matter of which modules are included in the initrd. The md indication is interesting. Could the raid flag be set on the partition?

[jankushka]

Re: no root device found - can't boot

It sounds like root is using a filesystem that is supported in the older initer and not the newer.

it's ext3.
so it shouldn't be a problem.
it says it doesn't find the root fs, but then the message in busybox also says it doesn't find the device (/dev/sda5).
so the fact that no root fs is found seems to be a consequence of the root device not being found.

The md indication is interesting. Could the raid flag be set on the partition?

i'm pretty sure it's set to 83, but i will double check.
thanks for the suggestion.
this md thing makes me think initrd looks for a md device instead of a plain simple linux partition.
for some reason...

[Qqmike]

Re: no root device found - can't boot

You are sure this has nothing to do with the inode size? --something you might understand better than I.
http://kubuntuforums.net/forums/inde...opic=3099193.0

[jankushka]

Re: no root device found - can't boot

You are sure this has nothing to do with the inode size? --something you might understand better than I.
http://kubuntuforums.net/forums/inde...opic=3099193.0

very interesting.
will look into this as well.
right now we have the old hh grub into the mbr.
so, i will reinstall grub into the mbr (will hard wipe the mbr with dd, if necessary) from jj.
thanks.

[jankushka]

Re: no root device found - can't boot [SOLVED]

had a chance to put my hands on my friend's pc again...

it was not a problem with grub (i grub-installed the new one and had the same behaviour).
it was not a problem with the partition type (it was correctly set to 83).
it simply was a question of uninstalling dmraid and its dependencies.
upon removal of the dmraid package, initrd was rebuilt and all was fixed.
the question remains as to why dmraid was used in the initrd.
funny situation, but all well was ends well.

thanks everybody again for your help.

cheers.