diff --git a/mlair/data_handler/iterator.py b/mlair/data_handler/iterator.py
index f2e3b689512ee99524eef8445f84a5a3bdb60f90..8c7cc6c51a59cda679aaf06c3563084a89db5a2a 100644
--- a/mlair/data_handler/iterator.py
+++ b/mlair/data_handler/iterator.py
@@ -9,6 +9,7 @@ import math
 import os
 import shutil
 import pickle
+import logging
 import dill
 from typing import Tuple, List
 
@@ -142,6 +143,7 @@ class KerasIterator(keras.utils.Sequence):
         remaining = None
         mod_rank = self._get_model_rank()
         for data in self._collection:
+            logging.info(f"prepare batches for {str(data)}")
             X = data.get_X(upsampling=self.upsampling)
             Y = [data.get_Y(upsampling=self.upsampling)[0] for _ in range(mod_rank)]
             if self.upsampling: