diff --git a/README.cloud b/README.cloud
index 9be44d0898..61d98d13e8 100644
--- a/README.cloud
+++ b/README.cloud
@@ -64,7 +64,7 @@ Setting up a new persistent cloud host:
 3) Create persistent storage disk for the instance (if necessary.. you might not
    need this).
 
-    nova volume-create --display-name SOME_NAME SIZE
+    nova volume-create --display-name SOME_NAME SIZE_IN_GB
 
 4) Add to ansible inventory in the persistent-cloud group.
    You should use the FQDN for this and not the IP.  Names are good.