error mounting root partition

[FLOP]

Experts, Gurus, anyone who knows more than me,

I cannot seem to add an external disk with out the machine getting stuck during boot. It is a previously partitioned disk from a SUN which I need to mount RO locally. I believe this is possible on RH7.3

The disk is recognised correctly by the machine and the boot sequence gets as far as mounting /proc then tries to mount the root partition RO and then comes up with an error:

Mounting /proc filesystem
Creating root device
Mounting root filesystem
mount: error 6 mounting ext3
pivotroot: pivot_root(/sysroot,/sysroot/initrd) failed: 2
Freeing unused kernel memory: 340k freed
Kernel panic: No init found. Try passing init= option to kernel.


I believe that the logical device assignment is being done sequentially at boot up and when I reboot with a new disk the previous logical assignments are all forgotten so it is looking fo rhte root partition on the new disk which of course it cannot find. Rightly or wrongly this is how I have explained the need for filesystems to be mounted by label rather than blocked device but it isn't helping me.

Any advice greatly appreciated.

Learner

 

[Morsing]

If it was partitioned on a SUN you need that support put into the kernel. Have you done that??

Cheers Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support

 

[Morsing]

You don't want to actually boot from the external disk, do you?? What type of disks do you have?? Are they all SCSI??

Cheers Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support

 

[FLOP]

Henrik

The machine has 3 internal scsi disks and an adaptec card on which I have attached the external disk. No I do not want to boot from the external SUN disk, rather just need to make the SUN filesystem available RO to transfer data.

Your suggestion that I need to put SUN support into the kernel sounds promising. Can you suggest how I might do this?

regards
James

 

[Morsing]

Ok. Step by step (assuming you've never built a kernel before:

1) cd /usr/src/linux
2) make xconfig
3) Go through the whole lot (don't skip anything, get this done now). This will take you hours if you're familiar with it.
Somewhere you'll find "support for SUN disk labels".

4) save & exit
5) make bzImage && make modules && make modules_install
6) cp arch/i386/boot/bzImage /lilo/vmlinuz-200203 (today's date).
7) Edit /etc/lilo.conf and add the following:

image=/boot/vmlinuz-200203
label=SUNdisk

8) run 'lilo'
9) reboot (if no errors during all of this)
10) When the LILO: prompt shows up press <TAB>
11) Type 'SUNdisk' <ENTER>

If this work you need to make that kernel the default kernel.
You migth still have a problem with SCSI IDs though, which is why it stops at boot.
Make sure the external device has an ID that is higher than the other disks.

Cheers Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support

 

[FLOP]

Henrik

I have discovered that my main problem is that I cannot seem to get the machine to go to the correct disk for the root partition. Despite anything I do in the BIOS which I expect would point the system towards the original internal disk it always assigns the external disk as /dev/sda. So this is my first problem and I am very confused by it.

Trying everything including recompiling kernel as in this example:

http://www.cs.helsinki.fi/linux/linux-kernel/2001-19/0808.html

thanks
J

 

[Morsing]

You need to change the SCSI IDs.
On the back of the external drive, there are two small buttons and a number. Change that number by pressing + several times.

Cheers Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support

 

[FLOP]

Henrik

It seems to be a bit more complicated than that. The three internal disks are on one integrated scsi bus whilst the external is attached to an adaptec 39160. The problem is that the machine finds the /boot partition on the first internal disk, then appears to mount the / partition RO. Then RH7.3 scans the scsibuses to build the /dev directory at unfortunately it scans the adaptec card first and in doing so assigns /dev/sda to the external disk. Then when it tries to pivotroot it remounts a different partition as / at which point it fails. I know that I can simply change the grub.conf to reflect the new location of root but I don't want to have to do this every time I add or remove an external disk. I would rather have the scsi bus scan order changed to always scan the internal bus first.

rgds james

 

[Morsing]

The problem is that there's no such thing as internal/external as seen from the system. I don't even know if it would help to move the adapter to another slot.

Maybe you can pass an option the the kernel at boot time but I don't know what it would be?? Smething that lists the IRQs in a different order??

Maybe you should take this to the kernel mailing list??

Cheers Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support