diff --git a/swh/storage/backfill.py b/swh/storage/backfill.py
--- a/swh/storage/backfill.py
+++ b/swh/storage/backfill.py
@@ -453,7 +453,7 @@
         return str(bound)
 
 
-MANDATORY_KEYS = ["storage_dbconn", "journal_writer"]
+MANDATORY_KEYS = ["storage", "journal_writer"]
 
 
 class JournalBackfiller:
@@ -480,6 +480,12 @@
                 " provided: %s" % (",".join(missing_keys),)
             )
 
+        if "cls" not in config["storage"] or config["storage"]["cls"] != "local":
+            raise ValueError(
+                "swh storage backfiller must be configured to use a local"
+                " (PostgreSQL) storage"
+            )
+
     def parse_arguments(self, object_type, start_object, end_object):
         """Parse arguments
 
@@ -519,7 +525,7 @@
             object_type, start_object, end_object
         )
 
-        db = BaseDb.connect(self.config["storage_dbconn"])
+        db = BaseDb.connect(self.config["storage"]["db"])
         writer = KafkaJournalWriter(**self.config["journal_writer"])
         for range_start, range_end in RANGE_GENERATORS[object_type](
             start_object, end_object
diff --git a/swh/storage/tests/test_backfill.py b/swh/storage/tests/test_backfill.py
--- a/swh/storage/tests/test_backfill.py
+++ b/swh/storage/tests/test_backfill.py
@@ -21,7 +21,7 @@
         "prefix": "swh.tmp_journal.new",
         "client_id": "swh.journal.client.test",
     },
-    "storage_dbconn": "service=swh-dev",
+    "storage": {"cls": "local", "db": "service=swh-dev"},
 }
 
 
@@ -212,7 +212,7 @@
             "client_id": "kafka_writer-2",
             "prefix": prefix2,
         },
-        "storage_dbconn": swh_storage_backend_config["db"],
+        "storage": swh_storage_backend_config,
     }
 
     # Backfilling