Comment 6 for bug 1241869

After internet research following post solved my problem : http://ubuntuforums.org/showthread.php?t=1965734
Changed the settings in /etc/sysctl.d/30-iscsitarget.conf and there the net.ipv4.tcp_mem Parameter which was 1048576 to 4096 87380 1048576. After that $ service procps restart nad $ apt-get update && apt-get upgrade. Update ended successfull. But -> nova-novncproxy service dies after somtime...