Public bug reported: 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 ** Affects: linux (Ubuntu) Importance: Undecided Status: New -- 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
