Hi, opened a ticket with the ceph-guys, and it turned out to be a bug in "librados aio flush".
With latest "wip-librados-aio-flush (bobtail)" I got no error even with _very_ high load. Thnx for the attention ;) Oliver. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1207686 Title: qemu-1.4.0 and onwards, linux kernel 3.2.x, heavy I/O leads to kernel_hung_tasks_timout_secs message and unresponsive qemu-process Status in QEMU: New Bug description: Hi, after some testing I tried to narrow down a problem, which was initially reported by some users. Seen on different distros - debian 7.1, ubuntu 12.04 LTS, IPFire-2.3 as reported by now. All using some flavour of linux-3.2.x kernel. Tried e.g. under Ubuntu an upgrade to "Linux 3.8.0-27-generic x86_64" which solves the problem. Problem could be triggert with some workload ala: spew -v --raw -P -t -i 3 -b 4k -p random -B 4k 1G /tmp/doof.dat and in parallel do some apt-get install/remove/whatever. That results in a somewhat stuck qemu-session with the bad "kernel_hung_task..." messages. A typical command-line is as follows: /usr/local/qemu-1.6.0/bin/qemu-system-x86_64 -usbdevice tablet -enable-kvm -daemonize -pidfile /var/run/qemu-server/760.pid -monitor unix:/var/run/qemu-server/760.mon,server,nowait -vnc unix:/var/run /qemu-server/760.vnc,password -qmp unix:/var/run/qemu- server/760.qmp,server,nowait -nodefaults -serial none -parallel none -device virtio-net-pci,mac=00:F1:70:00:2F:80,netdev=vlan0d0 -netdev type=tap,id=vlan0d0,ifname=tap760i0d0,script=/etc/fcms/add_if.sh,downscript=/etc/fcms/downscript.sh -name 1155823384-4 -m 512 -vga cirrus -k de -smp sockets=1,cores=1 -device virtio-blk-pci,drive=virtio0 -drive format=raw,file=rbd:1155823384/vm-760-disk-1.rbd:rbd_cache=false,cache=writeback,if=none,id=virtio0,media=disk,index=0,aio=native -drive format=raw,file=rbd:1155823384/vm-760-swap-1.rbd:rbd_cache=false,cache=writeback,if=virtio,media=disk,index=1,aio=native -drive if=ide,media=cdrom,id=ide1-cd0,readonly=on -drive if=ide,media=cdrom,id=ide1-cd1,readonly=on -boot order=dc no "system_reset", "sendkey ctrl-alt-delete" or "q" in monitoring- session is accepted, need to hard-kill the process. Please give any advice on what to do for tracing/debugging, because the number of tickets here are raising, and noone knows, what users are doing inside their VM. Kind regards, Oliver Francke. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1207686/+subscriptions
