diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 194229a5..42e11207 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -2585,8 +2585,9 @@ sub vm_start {
 	    vm_monitor_command($vmid, $cmd);
 	};
 
-	if (my $migrate_downtime =
-	    $conf->{migrate_downtime} || $defaults->{migrate_downtime}) {
+	my $migrate_downtime = $defaults->{migrate_downtime};
+	$migrate_downtime = $conf->{migrate_downtime} if defined($conf->{migrate_downtime});
+	if (defined($migrate_downtime)) {
 	    my $cmd = "migrate_set_downtime ${migrate_downtime}";
 	    eval { vm_monitor_command($vmid, $cmd); };
 	}
diff --git a/changelog.Debian b/changelog.Debian
index 562d7d87..d156c02b 100644
--- a/changelog.Debian
+++ b/changelog.Debian
@@ -1,6 +1,8 @@
 qemu-server (2.0-38) unstable; urgency=low
 
   * add directsync cache mode
+  
+  * fix bug #147: allow to set migrate_downtime to 0
 
  -- Proxmox Support Team <support@proxmox.com>  Wed, 11 Apr 2012 08:51:56 +0200