From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 1EA5791455 for ; Tue, 27 Sep 2022 13:50:43 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 03B871E0EC for ; Tue, 27 Sep 2022 13:50:13 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS for ; Tue, 27 Sep 2022 13:50:11 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id B6166445EE for ; Tue, 27 Sep 2022 13:50:11 +0200 (CEST) From: Fiona Ebner To: pve-devel@lists.proxmox.com Date: Tue, 27 Sep 2022 13:50:04 +0200 Message-Id: <20220927115004.121044-1-f.ebner@proxmox.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.032 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [proxmox.com, qemuserver.pm, qemumigrate.pm] Subject: [pve-devel] [PATCH qemu-server] migration: use copy-mode "write-blocking" for drive mirror X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 27 Sep 2022 11:50:43 -0000 Otherwise, there is nothing enforcing that the drive mirror is ready when the migration inactivates the block devices, which can lead to a failing assertion: > ../block/io.c:2026: bdrv_co_write_req_prepare: Assertion > `!(bs->open_flags & BDRV_O_INACTIVE)' failed. QAPI documentation of 'write-blocking' (currently the only alternative to the default 'background' mode): > when data is written to the source, write it (synchronously) to the > target as well. In addition, data is copied in background just like > in background mode. Reported in the community forum [0] (and likely [1]). Reproduced consistently with a 1 core, 1 GiB RAM, 4 GiB disk Debian 11 VM. I added a sleep of 5 second before issuing the migrate QMP command and executed the following in the VM after the drive-mirror became first ready: > fio --name=make-mirror-work --size=100M --direct=1 --rw=randwrite \ > --bs=4k --ioengine=psync --numjobs=5 --runtime=60 --time_based This ensures that there is a large number of dirty clusters and that the mirror still has work to do when the block device is inactivated. [0] https://forum.proxmox.com/threads/111831/ [1] https://forum.proxmox.com/threads/100020/ Signed-off-by: Fiona Ebner --- PVE/QemuMigrate.pm | 14 +++++++++++++- PVE/QemuServer.pm | 6 +++++- 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/PVE/QemuMigrate.pm b/PVE/QemuMigrate.pm index d52dc8db..dd6b073e 100644 --- a/PVE/QemuMigrate.pm +++ b/PVE/QemuMigrate.pm @@ -831,7 +831,19 @@ sub phase2 { my $bitmap = $target->{bitmap}; $self->log('info', "$drive: start migration to $nbd_uri"); - PVE::QemuServer::qemu_drive_mirror($vmid, $drive, $nbd_uri, $vmid, undef, $self->{storage_migration_jobs}, 'skip', undef, $bwlimit, $bitmap); + PVE::QemuServer::qemu_drive_mirror( + $vmid, + $drive, + $nbd_uri, + $vmid, + undef, + $self->{storage_migration_jobs}, + 'skip', + undef, + $bwlimit, + $bitmap, + 1, + ); } } diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm index 4e85dd02..2901cd83 100644 --- a/PVE/QemuServer.pm +++ b/PVE/QemuServer.pm @@ -7450,7 +7450,7 @@ sub qemu_img_format { } sub qemu_drive_mirror { - my ($vmid, $drive, $dst_volid, $vmiddst, $is_zero_initialized, $jobs, $completion, $qga, $bwlimit, $src_bitmap) = @_; + my ($vmid, $drive, $dst_volid, $vmiddst, $is_zero_initialized, $jobs, $completion, $qga, $bwlimit, $src_bitmap, $write_blocking) = @_; $jobs = {} if !$jobs; @@ -7477,6 +7477,10 @@ sub qemu_drive_mirror { my $opts = { timeout => 10, device => "drive-$drive", mode => "existing", sync => "full", target => $qemu_target }; $opts->{format} = $format if $format; + # Relevant for migration, to ensure that the mirror will be ready (after being ready once) when + # the migration inactivates the block drives. + $opts->{'copy-mode'} = 'write-blocking' if $write_blocking; + if (defined($src_bitmap)) { $opts->{sync} = 'incremental'; $opts->{bitmap} = $src_bitmap; -- 2.30.2