diff --git a/SAS/DataManagement/StorageQueryService/cache.py b/SAS/DataManagement/StorageQueryService/cache.py
index 4b1747b8f355afec8b6b198d82501d6042ea6236..687efb4b0786df8a84f46eefb970296719be1158 100644
--- a/SAS/DataManagement/StorageQueryService/cache.py
+++ b/SAS/DataManagement/StorageQueryService/cache.py
@@ -191,11 +191,13 @@ class CacheManager:
             if path in path_cache:
                 path_cache[path]['needs_update'] = True
 
-    def getDiskUsagesForAllOtdbIds(self, force_update=False):
-        otdb_ids = []
+    def getOtdbIdsFoundOnDisk(self):
         with self._cacheLock:
             otdb_id2path_cache = self._cache['otdb_id2path']
-            otdb_ids = list(otdb_id2path_cache.keys())
+            return sorted(list(otdb_id2path_cache.keys()))
+
+    def getDiskUsagesForAllOtdbIds(self, force_update=False):
+        otdb_ids = self.getOtdbIdsFoundOnDisk()
 
         result = {}
         for otdb_id in otdb_ids:
diff --git a/SAS/DataManagement/StorageQueryService/rpc.py b/SAS/DataManagement/StorageQueryService/rpc.py
index 03d0afcee46a8bc9c32f3be7fe1519fc91d64f47..8cf9eb91c01afa4c652d6a1059d7f96f246af7b2 100644
--- a/SAS/DataManagement/StorageQueryService/rpc.py
+++ b/SAS/DataManagement/StorageQueryService/rpc.py
@@ -52,6 +52,9 @@ class StorageQueryRPC(RPCClientContextManagerMixin):
     def getDiskUsagesForAllOtdbIds(self, force_update=False):
         return self._rpc_client.execute('GetDiskUsagesForAllOtdbIds', force_update=force_update)
 
+    def getOtdbIdsFoundOnDisk(self):
+        return self._rpc_client.execute('GetOtdbIdsFoundOnDisk')
+
 def main():
     from pprint import pprint
     import sys
diff --git a/SAS/DataManagement/StorageQueryService/service.py b/SAS/DataManagement/StorageQueryService/service.py
index b318191be7bdea79007479ba59dd3230bd081a18..04faa44478a3a0c8cb7024437329e2aeb7f7499d 100644
--- a/SAS/DataManagement/StorageQueryService/service.py
+++ b/SAS/DataManagement/StorageQueryService/service.py
@@ -34,6 +34,7 @@ class StorageQueryHandler(ServiceMessageHandler):
         self.register_service_method('GetDiskUsageForProjectsDirAndSubDirectories', self.cache.getDiskUsageForProjectsDirAndSubDirectories)
         self.register_service_method('GetDiskUsageForPath', self.cache.getDiskUsageForPath)
         self.register_service_method('GetDiskUsagesForAllOtdbIds', self.cache.getDiskUsagesForAllOtdbIds)
+        self.register_service_method('GetOtdbIdsFoundOnDisk', self.cache.getOtdbIdsFoundOnDisk)
 
 def createService(exchange=DEFAULT_BUSNAME, broker=DEFAULT_BROKER,
                   mountpoint=CEP4_DATA_MOUNTPOINT, cache_manager=None):