diff --git a/weed/server/master_grpc_server_assign.go b/weed/server/master_grpc_server_assign.go
index 4f95b4ff6..c45184541 100644
--- a/weed/server/master_grpc_server_assign.go
+++ b/weed/server/master_grpc_server_assign.go
@@ -96,6 +96,7 @@ func (ms *MasterServer) Assign(ctx context.Context, req *master_pb.AssignRequest
 			}
 		}
 		if err != nil {
+			glog.V(0).Infof("assign %v %v: %v", req, option.String(), err)
 			stats.MasterPickForWriteErrorCounter.Inc()
 			lastErr = err
 			time.Sleep(200 * time.Millisecond)