From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:47364) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ggZyy-0003jF-4x for qemu-devel@nongnu.org; Mon, 07 Jan 2019 13:50:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ggZyw-0005RM-0o for qemu-devel@nongnu.org; Mon, 07 Jan 2019 13:50:40 -0500 Received: from indium.canonical.com ([91.189.90.7]:46520) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1ggZyv-0005Q5-RI for qemu-devel@nongnu.org; Mon, 07 Jan 2019 13:50:37 -0500 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.86_2 #2 (Debian)) id 1ggZyu-0004GN-N7 for ; Mon, 07 Jan 2019 18:50:36 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id ABAF92E80C7 for ; Mon, 7 Jan 2019 18:50:36 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Mon, 07 Jan 2019 18:38:54 -0000 From: Peter Maydell Reply-To: Bug 1810603 <1810603@bugs.launchpad.net> Sender: bounces@canonical.com References: <154670237006.5111.1505843603378488710.malonedeb@wampee.canonical.com> Message-Id: <154688633487.25463.13951540831161738324.launchpad@chaenomeles.canonical.com> Errors-To: bounces@canonical.com Subject: [Qemu-devel] [Bug 1810603] Re: QEMU QCow Images grow dramatically List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org ** Summary changed: - QEMU QCow Images crow dramatically + QEMU QCow Images grow dramatically -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1810603 Title: QEMU QCow Images grow dramatically Status in QEMU: New Bug description: I've recently migrated our VM infrastructure (~200 guest on 15 hosts) from vbox to Qemu (using KVM / libvirt). We have a master image (QEMU QCow v3) from which we spawn multiple instances (linked clones). All guests are being revert once per hour for security reasons. About 2 weeks after we successfully migrated to Qemu, we noticed that almost all disks went full across all 15 hosts. Our investigation showed that the initial qcow disk images blow up from a few gigabytes to 100GB and more. This should not happen, as we revert all VMs back to the initial snapshot once per hour and hence all changes that have been made to disks must be reverted too. We did an addition test with 24 hour time frame with which we could reproduce this bug as documented below. Initial disk image size (created on Jan 04): -rw-r--r-- 1 root root 7.1G Jan 4 15:59 W10-TS01-0.img -rw-r--r-- 1 root root 7.3G Jan 4 15:59 W10-TS02-0.img -rw-r--r-- 1 root root 7.4G Jan 4 15:59 W10-TS03-0.img -rw-r--r-- 1 root root 8.3G Jan 4 16:02 W10-CLIENT01-0.img -rw-r--r-- 1 root root 8.6G Jan 4 16:05 W10-CLIENT02-0.img -rw-r--r-- 1 root root 8.0G Jan 4 16:05 W10-CLIENT03-0.img -rw-r--r-- 1 root root 8.3G Jan 4 16:08 W10-CLIENT04-0.img -rw-r--r-- 1 root root 8.1G Jan 4 16:12 W10-CLIENT05-0.img -rw-r--r-- 1 root root 8.0G Jan 4 16:12 W10-CLIENT06-0.img -rw-r--r-- 1 root root 8.1G Jan 4 16:16 W10-CLIENT07-0.img -rw-r--r-- 1 root root 7.6G Jan 4 16:16 W10-CLIENT08-0.img -rw-r--r-- 1 root root 7.6G Jan 4 16:19 W10-CLIENT09-0.img -rw-r--r-- 1 root root 7.5G Jan 4 16:21 W10-ROUTER-0.img -rw-r--r-- 1 root root 18G Jan 4 16:25 W10-MASTER-IMG.qcow2 Disk image size after 24 hours (printed on Jan 05): -rw-r--r-- 1 root root 13G Jan 5 15:07 W10-TS01-0.img -rw-r--r-- 1 root root 8.9G Jan 5 14:20 W10-TS02-0.img -rw-r--r-- 1 root root 9.0G Jan 5 15:07 W10-TS03-0.img -rw-r--r-- 1 root root 10G Jan 5 15:08 W10-CLIENT01-0.img -rw-r--r-- 1 root root 11G Jan 5 15:08 W10-CLIENT02-0.img -rw-r--r-- 1 root root 11G Jan 5 15:08 W10-CLIENT03-0.img -rw-r--r-- 1 root root 11G Jan 5 15:08 W10-CLIENT04-0.img -rw-r--r-- 1 root root 19G Jan 5 15:07 W10-CLIENT05-0.img -rw-r--r-- 1 root root 14G Jan 5 15:08 W10-CLIENT06-0.img -rw-r--r-- 1 root root 9.7G Jan 5 15:07 W10-CLIENT07-0.img -rw-r--r-- 1 root root 35G Jan 5 15:08 W10-CLIENT08-0.img -rw-r--r-- 1 root root 9.2G Jan 5 15:07 W10-CLIENT09-0.img -rw-r--r-- 1 root root 41G Jan 5 15:08 W10-ROUTER-0.img -rw-r--r-- 1 root root 18G Jan 4 16:25 W10-MASTER-IMG.qcow2 You can reproduce this bug as follow: 1) create an initial disk image 2) create a linked clone 3) create a snapshot of the linked clone 4) revert the snapshot every X minutes / hours Due the described behavior / bug, our VM farm is completely down at the moment (as we run out of disk space on all host systems). A quick fix for this bug would be much appreciated. Host OS: Ubuntu 18.04.01 LTS Kernel: 4.15.0-43-generic Qemu: 3.1.0 libvirt: 4.10.0 Guest OS: Windows 10 64bit To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1810603/+subscriptions