Hi Apollon, I did not experience any issues since I changed disk_aio to native and disk_cache to none on all instances and it was 3 weeks ago. So I believe you can close this bug now.
Beside that, maybe these parameters should be the new default in the ganeti package or maybe directly in qemu-kvm package? Otherwise I will put this tips somewhere in the debian wiki maybe that could help other people. Thanks again for you help. Regards, Thomas
