diff --git a/etc/inc/config.inc b/etc/inc/config.inc
index 6f9a990cf7..b34b4e8a90 100644
--- a/etc/inc/config.inc
+++ b/etc/inc/config.inc
@@ -2092,6 +2092,9 @@ endif;
 		exec("cd $rrddbpath;/usr/bin/find *-quality.rrd", $databases);
 		rsort($databases);
 		foreach($databases as $database) {
+			$xmldump = "{$database}.old.xml";
+			$xmldumpnew = "{$database}.new.xml";
+
 			log_error("Migrate RRD database {$rrddbpath}/{$database} to new format");
 			echo "Migrate RRD database {$rrddbpath}/{$database} to new format \n";
 			mwexec("$rrdtool tune {$rrddbpath}{$database} -r roundtrip:delay 2>&1");