From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45006) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dU41v-0008HX-O9 for qemu-devel@nongnu.org; Sun, 09 Jul 2017 00:41:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dU41s-0007TG-Hu for qemu-devel@nongnu.org; Sun, 09 Jul 2017 00:41:11 -0400 Received: from indium.canonical.com ([91.189.90.7]:44025) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dU41s-0007RK-CN for qemu-devel@nongnu.org; Sun, 09 Jul 2017 00:41:08 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.76 #1 (Debian)) id 1dU41p-0007e7-G7 for ; Sun, 09 Jul 2017 04:41:05 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id 6FFC32E80E6 for ; Sun, 9 Jul 2017 04:41:05 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Sun, 09 Jul 2017 04:21:24 -0000 From: Launchpad Bug Tracker <1689499@bugs.launchpad.net> Reply-To: Bug 1689499 <1689499@bugs.launchpad.net> Sender: bounces@canonical.com References: <149431685971.9593.12799784331390412455.malonedeb@gac.canonical.com> Message-Id: <149957408476.29932.5509044476381495598.malone@loganberry.canonical.com> Errors-To: bounces@canonical.com Subject: [Qemu-devel] [Bug 1689499] Re: copy-storage-all/inc does not easily converge with load going on List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org [Expired for QEMU because there has been no activity for 60 days.] ** Changed in: qemu Status: Incomplete =3D> Expired -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1689499 Title: copy-storage-all/inc does not easily converge with load going on Status in QEMU: Expired Bug description: Hi, for now this is more a report to discuss than a "bug", but I wanted to be= sure if there are things I might overlook. I'm regularly testing the qemu's we have in Ubuntu which currently are 2.0, 2.5, 2.6.1, 2.8 plus a bunch of patches. And for all sorts of verification upstream every now and then. I recently realized that the migration options around --copy-storage-[all= /inc] seem to have got worse at converging on migration. Although it is not= a hard commit that is to be found, it just seems more likely to occur the = newer the qemu versions is. I assume that is partially due to guest perform= ance optimization that keep it busy. To a user it appears as a hanging migration being locked up. But let me outline what actually happens: - Setup without shared storage - Migration using --copy-storage-all/--copy-storage-inc - Working fine with idle guests - If the guests is busy the migration does take like forever (1 vCPU that= are busy with 1 CPU, 1 memory and one disk hogging processes) - statistically seems to trigger more likely on newer qemu's (might be a = red herring) The background workloads are most trivial burners: - cpu: md5sum /dev/urandom - memory: stress-ng -m 1 --vm-keep --vm-bytes 256M - disk: while /bin/true; do dd if=3D/dev/urandom of=3D/var/tmp/mjb.1 bs= =3D4M count=3D100; done We are talking about ~1-2 minutes on qemu 2.5 (4 tries x 3 architectures) and 2-10+ hours on >=3Dqemu 2.6.1. I say it is likely not a bug, but more a discussion as I can easily avoid= hanging via either: - timeouts (--timeout, ...) to abort or suspend to migrate it - --auto-converge ( I had only one try, but it seemed to help by slowing = down the load generators) So you might say "that is all as it should be, and the users can use the further options to mitigate" and I'm all fine with that. In that case the bug still serves as a "searchable" document of some kind for others triggering the same case. But if anything comes to your mind that need better handling around this case lets start to discuss more deeply about it. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1689499/+subscriptions