diff --git a/README.rst b/README.rst
index f15bff7..3db3493 100644
--- a/README.rst
+++ b/README.rst
@@ -184,6 +184,15 @@
           user_storage: 0
         ....
 
+Maximum size of image
+
+.. code-block:: yaml
+
+    glance:
+      server:
+        ....
+        image_size_cap: 2199023255552 # 2TB, twice current default
+
 Configuring TLS communications
 ------------------------------