On Tue, Sep 20, 2016 at 09:40:22 -0400, Corey S. McQuay wrote: > Currently Libvirt allows attempts to migrate read only disks. Qemu cannot handle this as read only > disks cannot be written to on the destination system. The end result is a cryptic error message > and a failed migration. This is not necessarily true. Read only disks can sometimes be in fact backed by storage that is writable and it's desired to be migrated. I think you want to specify which storage to migrate using the VIR_MIGRATE_PARAM_MIGRATE_DISKS migration parameter for virDomainMigrate3. http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainMigrate3 http://libvirt.org/html/libvirt-libvirt-domain.html#VIR_MIGRATE_PARAM_MIGRATE_DISKS Virsh also implements support for that flag. > This patch causes migration to fail earlier and provides a meaningful error message stating that > migrating read only disks is not supported. > > Signed-off-by: Corey S. McQuay <csmcquay@xxxxxxxxxxxxxxxxxx> > Reviewed-by: Jason J. Herne <jjherne@xxxxxxxxxxxxxxxxxx> > Reviewed-by: Boris Fiuczynski <fiuczy@xxxxxxxxxxxxxxxxxx> > --- > src/qemu/qemu_migration.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c > index e451ef6..011f349 100644 > --- a/src/qemu/qemu_migration.c > +++ b/src/qemu/qemu_migration.c > @@ -2157,6 +2157,13 @@ qemuMigrationDriveMirror(virQEMUDriverPtr driver, > if (!qemuMigrateDisk(disk, nmigrate_disks, migrate_disks)) > continue; > > + if (disk->src->readonly) { > + virReportError(VIR_ERR_OPERATION_UNSUPPORTED, > + _("Cannot migrate read-only disk %s"), > + disk->dst); > + goto cleanup; > + } NACK this would break the above use case. You want to specify explicitly which storage to migrate using the above described API. Peter -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list