diff --git a/tests/run_3osds.sh b/tests/run_3osds.sh
index 6ffe4b63..b9a3e64c 100644
--- a/tests/run_3osds.sh
+++ b/tests/run_3osds.sh
@@ -19,10 +19,10 @@ fi
 
 if [ "$IMMEDIATE_COMMIT" != "" ]; then
     NO_SAME="--journal_no_same_sector_overwrites true --journal_sector_buffer_count 1024 --disable_data_fsync 1 --immediate_commit all --log_level 10"
-    $ETCDCTL put /vitastor/config/global '{"recovery_queue_depth":1,"osd_out_time":1,"immediate_commit":"all"}'
+    $ETCDCTL put /vitastor/config/global '{"recovery_queue_depth":1,"osd_out_time":1,"immediate_commit":"all","client_enable_writeback":true}'
 else
     NO_SAME="--journal_sector_buffer_count 1024 --log_level 10"
-    $ETCDCTL put /vitastor/config/global '{"recovery_queue_depth":1,"osd_out_time":1}'
+    $ETCDCTL put /vitastor/config/global '{"recovery_queue_depth":1,"osd_out_time":1,"client_enable_writeback":true}'
 fi
 
 start_osd_on()