I am running Windows 2008R2 as KVM guest on Ubuntu 12.04 hypervisor. Disk controller and network card are virtio devices with drivers from https://launchpad.net/kvm-guest-drivers-windows/+download (virtio-win-drivers-20120712-1.iso).
Everything worked fine until I changed disk controller cache from the default (writethrough) to writeback. This introduced occasional blue screens. I noticed that they are linked to high disk IO. For example restoring over 1GB of backup files will results in a blue screen on around 4 out of 5 attempts. Also Windows update crashes the system sometimes. When idle the system will run fine for hours or sometimes even days.
After removing cache='writeback' from the config everything came back to normal.
qemu-kvm:
Installed: 1.0+noroms-0ubuntu14.8
Candidate: 1.0+noroms-0ubuntu14.8
Version table:
*** 1.0+noroms-0ubuntu14.8 0
500 http://archive.ubuntu.com/ubuntu/ precise-updates/main amd64 Packages
100 /var/lib/dpkg/status
1.0+noroms-0ubuntu14.7 0
500 http://security.ubuntu.com/ubuntu/ precise-security/main amd64 Packages
1.0+noroms-0ubuntu13 0
500 http://archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
Hi Jacek,
I haven't seen other writeback related crashes and the info so far isn't enough to debug anything.
Did you get any related host logs on the crashes.
In dmesg or the guest log in /var/log/