apport information ** Description changed:
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 + --- + AlsaDevices: + total 0 + crw-rw---- 1 root audio 116, 1 Jul 21 13:53 seq + crw-rw---- 1 root audio 116, 33 Jul 21 13:53 timer + AplayDevices: Error: [Errno 2] No such file or directory + ApportVersion: 2.14.1-0ubuntu3.2 + Architecture: amd64 + ArecordDevices: Error: [Errno 2] No such file or directory + AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: + CRDA: Error: [Errno 2] No such file or directory + DistroRelease: Ubuntu 14.04 + HibernationDevice: RESUME=/dev/mapper/bootdisk-swap_1 + IwConfig: Error: [Errno 2] No such file or directory + MachineType: Supermicro H8DG6/H8DGi + Package: linux (not installed) + PciMultimedia: + + ProcEnviron: + TERM=screen + PATH=(custom, no user) + XDG_RUNTIME_DIR=<set> + LANG=en_US.UTF-8 + SHELL=/bin/bash + ProcFB: 0 VESA VGA + ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-29-generic root=/dev/mapper/bootdisk-root ro quiet splash rootdelay=120 nomdmonddf nomdmonisw vt.handoff=7 + ProcVersionSignature: Ubuntu 3.13.0-29.53-generic 3.13.11.2 + RelatedPackageVersions: + linux-restricted-modules-3.13.0-29-generic N/A + linux-backports-modules-3.13.0-29-generic N/A + linux-firmware 1.127.2 + RfKill: Error: [Errno 2] No such file or directory + Tags: trusty + Uname: Linux 3.13.0-29-generic x86_64 + UpgradeStatus: No upgrade log present (probably fresh install) + UserGroups: root + _MarkForUpload: True + dmi.bios.date: 11/25/2013 + dmi.bios.vendor: American Megatrends Inc. + dmi.bios.version: 3.5 + dmi.board.asset.tag: To Be Filled By O.E.M. + dmi.board.name: H8DG6/H8DGi + dmi.board.vendor: Supermicro + dmi.board.version: 1.0 + dmi.chassis.asset.tag: To Be Filled By O.E.M. + dmi.chassis.type: 17 + dmi.chassis.vendor: Supermicro + dmi.chassis.version: 1234567890 + dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr3.5:bd11/25/2013:svnSupermicro:pnH8DG6/H8DGi:pvr1234567890:rvnSupermicro:rnH8DG6/H8DGi:rvr1.0:cvnSupermicro:ct17:cvr1234567890: + dmi.product.name: H8DG6/H8DGi + dmi.product.version: 1234567890 + dmi.sys.vendor: Supermicro ** Attachment added: "BootDmesg.txt" https://bugs.launchpad.net/bugs/1344430/+attachment/4159604/+files/BootDmesg.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1344430 Title: 10-15% iowait on kvm instances on Ubuntu 14.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1344430/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs