1 files changed, 41 insertions, 0 deletions
diff --git a/results/classifier/105/KVM/1201447 b/results/classifier/105/KVM/1201447
new file mode 100644
index 00000000..f03ca992
--- /dev/null
+++ b/results/classifier/105/KVM/1201447
@@ -0,0 +1,41 @@
+KVM: 0.978
+device: 0.922
+other: 0.873
+graphic: 0.669
+semantic: 0.630
+mistranslation: 0.623
+instruction: 0.599
+socket: 0.536
+network: 0.462
+vnc: 0.459
+boot: 0.446
+assembly: 0.244
+
+Blue screen when disk uses cache='writeback'
+
+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/libvirt/qemu/<guestname>.log?
+
+[Expired for qemu (Ubuntu) because there has been no activity for 60 days.]
+