[pve-devel] [PATCH qemu-server stable-bookworm v2 4/4] migration: tell users to upgrade if nets-host-mtu is required but not supported

Fiona Ebner f.ebner at proxmox.com
Tue Sep 9 11:17:00 CEST 2025


See also commit "migration: only use nets-host-mtu for PVE 8 target if
actually required". Tell people to upgrade when the target does not
support preserving the VirtIO-net MTU yet and that is required for the
migration at hand.

Suggested-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
---
 src/PVE/QemuMigrate.pm | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/PVE/QemuMigrate.pm b/src/PVE/QemuMigrate.pm
index ea35e54d..22688e48 100644
--- a/src/PVE/QemuMigrate.pm
+++ b/src/PVE/QemuMigrate.pm
@@ -1010,6 +1010,7 @@ 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
@@ -1067,11 +1068,16 @@ 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"
-- 
2.39.5





More information about the pve-devel mailing list