Kernel problems with unionfs and Ubuntu gutsy

[Tim Cutts]

On 25 Feb 2008, at 11:07 am, Tim Cutts wrote:

>
> On 21 Feb 2008, at 3:42 pm, R. F. Grant wrote:
>
>> After trying many kernels, I also find an extra annoyance. The new  
>> PCs
>> contain
>> Intel Q35 motherboards which contain a known bug: they will not  
>> boot from a
>> regular kernel unless you add pci=nommconf or acpi=off. There is a  
>> patch
>> that
>> is supposed to fix this for 2.6.24 kernels, although I have not had  
>> much
>> luck
>> with this.
>
> I've successfully FAI installed HP Deskpro 7800 desktops, which have  
> a Q35 chipset, using FAI 3.1.8 with a 2.6.24 kernel.  The kicker was  
> the e1000e ethernet driver that these machines need.  Neither of the  
> above kernel options were required with that kernel (this was the  
> 2.6.24-1-686 package from current Debian unstable, rebuilt for etch)
>
> I can't address your issues specifically but the above approach  
> worked fine for me.

I should add that the steps I took to make this sid kernel work for  
FAI 3.1.8 were as follows:

1)  Re-build it on an etch system so that the dependencies were correct
2)  Add it to our local debarchiver repository, so that apt can see it
3)  chroot into the FAI NFS root on the FAI server and
3a) Install the new kernel package
3b) rebuild the initrd file to expect the root filesystem to be NFS  
(without this, you get a kernel panic because it can't find the root  
filesystem)
4)  Copy the vmlinuz and initrd files out of the NFS root to the tftp  
directory
5)  Add an initrd= stanza to the pxelinux.cfg file so that the initrd  
gets loaded when the nodes PXE boot

I imagine some of this is already in place if you use FAI 3.2.4,  
because support for initrd images is designed into that version, isn't  
it?  It's worth noting that installing Debian etch on these HP dc7800p  
machines still requires us to use an additional graphics card in the  
machines; the Q35 graphics chip requires X.org stuff way newer than  
what's in etch, so we just slap in an nVidia card in each machine  
(with the additional advantage that it's DVI; the X packages'  
autoprobing of the monitor resolution seems to work much better that  
way, especially with cheaper widescreen -- 1920x1200 -- monitors, such  
as the Samsung SyncMaster 245B that I have in front of me)

Basically, the Linux support for recent HP deskpros is shaky to say  
the least.  Both dc7700 and dc7800 require very recent kernels if you  
don't want to have to do the acpi=off hack (which has other problems -  
as soon as you switch off ACPI on these machines the interrupt  
handling goes to hell, and the mouse becomes very erratic in its  
responsiveness). I fear this problem is going to become widespread  
though - other cheap business desktops like the Dell 755 are using the  
same chipset now.

I'm still not convinced even with the 2.6.24 kernel that everything is  
absolutely right - in particular the SATA disk performance seems  
pretty poor.

But none of this is relevant to FAI so I'll shut up now.  :-)

Tim


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