diff --git a/lib/ghtorrent/adapters/mongo_persister.rb b/lib/ghtorrent/adapters/mongo_persister.rb
index 5893620..a2b9e92 100644
--- a/lib/ghtorrent/adapters/mongo_persister.rb
+++ b/lib/ghtorrent/adapters/mongo_persister.rb
@@ -130,7 +130,7 @@ def mongo
 				 :user => uname, 
 				 :auth_source => 'admin',
          :read => {
-           :mode => :secondary_preferred
+           :mode => :secondary
          },
          :retry_reads => true,
          :retry_writes => true,