From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46992) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cmLrO-0007An-1M for qemu-devel@nongnu.org; Fri, 10 Mar 2017 09:49:39 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cmLrL-0005LT-Ea for qemu-devel@nongnu.org; Fri, 10 Mar 2017 09:49:38 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53612) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cmLrL-0005Kk-8I for qemu-devel@nongnu.org; Fri, 10 Mar 2017 09:49:35 -0500 Date: Fri, 10 Mar 2017 15:49:28 +0100 From: Kashyap Chamarthy Message-ID: <20170310144928.h5ozia5cybxstuwc@eukaryote> References: <3d1c16a1-ec05-0367-e569-64a63b34f2e3@redhat.com> <940ff281-82cd-18cf-160e-c5234f65db18@redhat.com> <9d6c61bc-4a95-ce72-3565-e498f9c2b351@redhat.com> <7829c1dc-9138-c784-dcc5-3c46ec9b5c05@innervision.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7829c1dc-9138-c784-dcc5-3c46ec9b5c05@innervision.pl> Subject: Re: [Qemu-devel] external snapshots freezes block device since qemu 2.8 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Piotr Rybicki Cc: qemu-devel@nongnu.org On Thu, Mar 09, 2017 at 11:11:09AM +0100, Piotr Rybicki wrote: > Hello there. > > I discovered, that since qemu 2.8 , external snapshots (very similar to: > http://wiki.libvirt.org/page/Live-disk-backup-with-active-blockcommit), When I wrote this Wiki page, I tested it only with regular QCOW2 files on EXT4 file system. > freezes block device after: > > # virsh blockcommit (...) > > There is no error message after completion of the command above. > I'm using gluster + ZFS fuse mount as a storage for a VM on gentoo. > libvirt debug showed nothing helpful. > With qemu <2.8 -: snapshots are working as expected. > > Is this a known issue? > Is it qemu or libvirt ? > > If it helps, how can i diagnose this further?a To see what libvirt is sending to QEMU, you can enable the debug log filters, which can give some clue: - In /etc/libvirt/libvirtd.conf, set these config attributes log_filters="1:libvirt 1:qemu 1:conf 1:security 3:event 3:json 3:file 3:object 1:util" log_outputs="1:file:/var/log/libvirt/libvirtd.log" - Restart libvirtd: $ systemctl restart libvirtd - Perform your `blockcommit` test. PS: A gentle reminder -- when reporting upstream, you'll likely better help if you at least test with the latest releases (libvirt-3.1.0, and QEMU 2.8), if not from Git. [...] -- /kashyap