diff --git a/src/test/perl/PostgresNode.pm b/src/test/perl/PostgresNode.pm
index c33723160e..4e3e23f013 100644
--- a/src/test/perl/PostgresNode.pm
+++ b/src/test/perl/PostgresNode.pm
@@ -469,12 +469,15 @@ sub init
 		{
 			print $conf "wal_level = replica\n";
 		}
-		print $conf "max_wal_size = 128MB\n";
+		print $conf "max_wal_senders = 10\n";
+		print $conf "max_replication_slots = 10\n";
 		print $conf "wal_log_hints = on\n";
 		print $conf "hot_standby = on\n";
 		# conservative settings to ensure we can run multiple postmasters:
 		print $conf "shared_buffers = 1MB\n";
 		print $conf "max_connections = 10\n";
+		# limit disk space consumption, too:
+		print $conf "max_wal_size = 128MB\n";
 	}
 	else
 	{