From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [IPv6:2a01:7e0:0:424::9]) by lore.proxmox.com (Postfix) with ESMTPS id E612A1FF191 for ; Tue, 9 Sep 2025 11:19:56 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 4FE7B43D8; Tue, 9 Sep 2025 11:20:00 +0200 (CEST) From: Fiona Ebner To: pve-devel@lists.proxmox.com Date: Tue, 9 Sep 2025 11:16:57 +0200 Message-ID: <20250909091918.32254-2-f.ebner@proxmox.com> X-Mailer: git-send-email 2.47.2 In-Reply-To: <20250909091918.32254-1-f.ebner@proxmox.com> References: <20250909091918.32254-1-f.ebner@proxmox.com> MIME-Version: 1.0 X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1757409544516 X-SPAM-LEVEL: Spam detection results: 0 AWL -0.023 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy 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 Subject: [pve-devel] [PATCH qemu-server master v2 1/4] migration: tell users to upgrade if nets-host-mtu is not supported 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: , Reply-To: Proxmox VE development discussion Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: pve-devel-bounces@lists.proxmox.com Sender: "pve-devel" In Proxmox VE 9, the default behavior for VirtIO network devices is to inherit the MTU from the bridge. This means that most migrations are potentially problematic when the nets-host-mtu parameter is not set, see commit 20c91f7f ("migration: preserve host_mtu for virtio-net devices"). While setting the parameter could be avoided in some cases, the information what MTU the target node bridges have is not readily available. Upgrading is already required to avoid actual problematic cases, so just tell people to upgrade when the target does not support preserving the VirtIO-net MTU yet in all cases. Suggested-by: Thomas Lamprecht Signed-off-by: Fiona Ebner --- src/PVE/QemuMigrate.pm | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/PVE/QemuMigrate.pm b/src/PVE/QemuMigrate.pm index 4381b542..8fbabdfa 100644 --- a/src/PVE/QemuMigrate.pm +++ b/src/PVE/QemuMigrate.pm @@ -1053,6 +1053,7 @@ sub phase2_start_local_cluster { }; my $target_replicated_volumes = {}; + my $target_nets_host_mtu_not_supported; # Note: We try to keep $spice_ticket secret (do not pass via command line parameter) # instead we pipe it through STDIN @@ -1110,11 +1111,16 @@ sub phase2_start_local_cluster { }, errfunc => sub { my $line = shift; + $target_nets_host_mtu_not_supported = 1 + if $line =~ m/^Unknown option: nets-host-mtu/; $self->log('info', "[$self->{node}] $line"); }, noerr => 1, ); + die "node $self->{node} is too old for preserving VirtIO-net MTU, please upgrade\n" + if $target_nets_host_mtu_not_supported; + die "remote command failed with exit code $exitcode\n" if $exitcode; die "unable to detect remote migration address\n" -- 2.47.2 _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel