Some things (like the hardware of the host) we get through apport-collect. It would be good to get a better understanding of the guest usage. Like how many guests, how much memory they get, how many vcpus. virtio disks and network and how are the guests connected to the network (NAT bridge, transparent bridge, openvswitch?). Are vdisk using raw images or qcov2, image files or partitions or logical volumes. Maybe then we can also replicate the issue in a test environment. Up to now I am not sure I ever was able to see the same issue or not. Oh and was there a specific stat or combination of stats that hints this is happening. Laggy terminal is hard to test for in some scripted way.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1344430 Title: 10-15% iowait on kvm instances on Ubuntu 14.04 Status in “linux” package in Ubuntu: Confirmed Bug description: After upgrading from Ubuntu 12.04 to Ubuntu 14.04 we began seeing 10-15% iowait on kvm guests. The guests had little to no load and yet the shell was laggy and commands took forever to respond (assuming you could even type them) # uname -a Linux kvm-andromeda 3.13.0-29-generic #53-Ubuntu SMP Wed Jun 4 21:00:20 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux # kvm --version QEMU emulator version 2.0.0 (Debian 2.0.0+dfsg-2ubuntu1.1), Copyright (c) 2003-2008 Fabrice Bellard I posted to Ubuntu Server and they suggested that I upgrade my kernel version. Relevant Mailing List discussion: https://lists.ubuntu.com/archives/ubuntu-server/2014-July/006925.html After installing a 3.14 kernel the performance returned to normal. kvm-andromeda:~# uname -a Linux kvm-andromeda 3.14.1-031401-generic #201404141220 SMP Mon Apr 14 16:21:48 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux --- ApportVersion: 2.14.1-0ubuntu3.2 Architecture: amd64 DistroRelease: Ubuntu 14.04 Package: linux (not installed) ProcEnviron: TERM=screen PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash Tags: trusty Uname: Linux 3.14.1-031401-generic x86_64 UnreportableReason: The running kernel is not an Ubuntu kernel UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: root _MarkForUpload: True To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1344430/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : firstname.lastname@example.org Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp