diff --git a/swh/vault/api/server.py b/swh/vault/api/server.py
--- a/swh/vault/api/server.py
+++ b/swh/vault/api/server.py
@@ -26,7 +26,13 @@
             },
         },
     }),
-    'cache': ('dict', {'root': '/tmp/vaultcache'}),
+    'cache': ('dict', {
+        'cls': 'pathslicing',
+        'args': {
+            'root': '/tmp/vaultcache',
+            'slicing': '0:1/1:5',
+        },
+    }),
     'vault_db': ('str', 'dbname=swh-vault')
 }
 
diff --git a/swh/vault/backend.py b/swh/vault/backend.py
--- a/swh/vault/backend.py
+++ b/swh/vault/backend.py
@@ -76,7 +76,7 @@
     """
     def __init__(self, config):
         self.config = config
-        self.cache = VaultCache(**self.config['cache'])
+        self.cache = VaultCache(self.config['cache'])
         self.db = None
         self.reconnect()
         self.smtp_server = smtplib.SMTP('localhost')
diff --git a/swh/vault/cache.py b/swh/vault/cache.py
--- a/swh/vault/cache.py
+++ b/swh/vault/cache.py
@@ -3,63 +3,45 @@
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
-import os
-
 from swh.model import hashutil
 from swh.objstorage import get_objstorage
-from swh.objstorage.objstorage_pathslicing import DIR_MODE
-
+from swh.objstorage.objstorage import compute_hash
 
-class VaultCache():
-    """The vault cache is an object storage that stores bundles
 
-    The current implementation uses a PathSlicingObjStorage to store
-    the bundles. The id of a content if prefixed to specify its type
-    and store different types of bundle in different folders.
+class VaultCache:
+    """The Vault cache is an object storage that stores Vault bundles.
 
+    This implementation computes sha1('<bundle_type>:<object_id>') as the
+    internal identifiers used in the underlying objstorage.
     """
 
-    def __init__(self, root):
-        self.root = root
-        self.storages = {}
+    def __init__(self, objstorage):
+        self.objstorage = get_objstorage(**objstorage)
 
     def add(self, obj_type, obj_id, content):
-        storage = self._get_storage(obj_type)
-        return storage.add(content, obj_id)
+        sid = self._get_internal_id(obj_type, obj_id)
+        return self.objstorage.add(content, sid)
 
     def get(self, obj_type, obj_id):
-        storage = self._get_storage(obj_type)
-        return storage.get(hashutil.hash_to_bytes(obj_id))
+        sid = self._get_internal_id(obj_type, obj_id)
+        return self.objstorage.get(hashutil.hash_to_bytes(sid))
 
     def delete(self, obj_type, obj_id):
-        storage = self._get_storage(obj_type)
-        return storage.delete(hashutil.hash_to_bytes(obj_id))
+        sid = self._get_internal_id(obj_type, obj_id)
+        return self.objstorage.delete(hashutil.hash_to_bytes(sid))
 
     def add_stream(self, obj_type, obj_id, content_iter):
-        storage = self._get_storage(obj_type)
-        return storage.add_stream(content_iter, obj_id)
+        sid = self._get_internal_id(obj_type, obj_id)
+        return self.objstorage.add_stream(content_iter, sid)
 
     def get_stream(self, obj_type, obj_id):
-        storage = self._get_storage(obj_type)
-        return storage.get_stream(hashutil.hash_to_bytes(obj_id))
+        sid = self._get_internal_id(obj_type, obj_id)
+        return self.objstorage.get_stream(hashutil.hash_to_bytes(sid))
 
     def is_cached(self, obj_type, obj_id):
-        storage = self._get_storage(obj_type)
-        return hashutil.hash_to_bytes(obj_id) in storage
-
-    def ls(self, obj_type):
-        storage = self._get_storage(obj_type)
-        yield from storage
-
-    def _get_storage(self, obj_type):
-        """Get the storage that corresponds to the object type"""
-
-        if obj_type not in self.storages:
-            fp = os.path.join(self.root, obj_type)
-            if not os.path.isdir(fp):
-                os.makedirs(fp, DIR_MODE, exist_ok=True)
-
-            conf = {'root': fp, 'slicing': '0:1/0:5', 'allow_delete': True}
-            self.storages[obj_type] = get_objstorage('pathslicing', conf)
+        sid = self._get_internal_id(obj_type, obj_id)
+        return hashutil.hash_to_bytes(sid) in self.objstorage
 
-        return self.storages[obj_type]
+    def _get_internal_id(self, obj_type, obj_id):
+        obj_id = hashutil.hash_to_hex(obj_id)
+        return compute_hash('{}:{}'.format(obj_type, obj_id).encode())
diff --git a/swh/vault/tests/vault_testing.py b/swh/vault/tests/vault_testing.py
--- a/swh/vault/tests/vault_testing.py
+++ b/swh/vault/tests/vault_testing.py
@@ -40,7 +40,14 @@
         self.vault_config = {
             'storage': self.storage_config,
             'vault_db': 'postgresql:///' + self.TEST_VAULT_DB_NAME,
-            'cache': {'root': self.cache_root.name}
+            'cache': {
+                'cls': 'pathslicing',
+                'args': {
+                    'root': self.cache_root.name,
+                    'slicing': '0:1/1:5',
+                    'allow_delete': True,
+                }
+            }
         }
         self.vault_backend = VaultBackend(self.vault_config)