Hi all, 
   I have to admit Martin might have been right: I upgraded to qemu 2.6.0 and still I see the same problem with virtio disks on my custom built Linux box. 

I create domain using the previously mentioned domain xml definition and try to install ubuntu from an iso. Earty on during the installation I get an error:
The attempt to mount a file system with type ext4 in Virtual disk1, partition#1 (vda1) at / failed
At this point the installation fails and I have to reboot the domain.

There obviously is something I'm missing since the same works on a ubuntu host machine but I have no idea what or how to debug it.

Any help is greatly appreciated.

Thanks!


On Wed, Oct 5, 2016 at 5:07 PM, Andrei Perietanu <andrei.perietanu@klastelecom.com> wrote:


On Wed, Oct 5, 2016 at 4:18 PM, Martin Kletzander <mkletzan@redhat.com> wrote:
On Wed, Oct 05, 2016 at 03:00:40PM +0100, Andrei Perietanu wrote:
Hi Andrea,
  Thanks for the reply;
  To shed some more light on the matter I performed a few more tests; each
time doing a clean install. I installed ubuntu14.04 as the guest OS,
keeping everything else the same.
On my custom Linux I've created ubuntu VMs before (using ide drivers) and
it all works file. This time I created the VM using virtio disk drivers and

So switching only the guest OS (keeping the host OS, domain XML and
everything) works, so how can the problem be anywhere else than the
guest OS?  You might be, most probably, missing some kernel option.
What is the difference between the installer and the system installed?
Are they using the same kernel?  Accessing the same things?

the installation didn't even finish. It reported a disk related error
saying it's not being able to read from /dev/vda. I restarted the
machine...same error.

You're adding more configurations into the mix, let's skip that and only
talk about what you had before, the IDE and ubuntu/your distro.

   Just to make sure that I have not messed anything up, I did the same on
the ubuntu host, so installed ubuntu guest on an ubuntu host uding the same
guest config xml. This time everything worked fine. So it looks like a
problem with the kvm virtio drivers.

   I was trying to stay away from updating the qemu package because adding
the package takes a long time (usually, because of missing dependencies),
but I'm not sure I have any other option at this point...


Are there that many since 1.1.2?  I don't think that much has changed.
But it should be solvable without updating (plus the update might not
fix it for you.
 
Let me try and recap what is happening :
On my custom embedded linux, using the same domain config xml, just changing the disk drivers and/or the iso
    Ubuntu.iso + ide disk drivers -> works
    Ubuntu.iso + virio disk drivers -> does not work; errors when reading from /dev/vda
    customLinuxOS.iso + virtio drivers -> does not seem to work; kernel panics and services stop working


On Ubuntu10.04 host, using the same domain config xml as before, just changing the iso
     Ubuntu.iso + virtio disk drivers -> vorks
     customLinuxOS.iso + virtio drivers -> works
    
This sounds to me like a problem with kvm virtio drivers (since when using ide drivers installing ubuntu as a guest works)

If there is anything I'm missing, or you think I should try ..I'm open to trying it.

Thanks,
Andrei 



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