diff --git a/README.md b/README.md
index 6ab71d0..498227f 100644
--- a/README.md
+++ b/README.md
@@ -79,7 +79,7 @@ To get you started, there is an example config file which you can use `examples/
         "host_ip": "10.81.2.105",
         "instance_name": "packer-centos-6-4",
         "instance_memory": "2048000000",
-        "root_disk_size": "5000000000",
+        "root_disk_size": "40000000000",
         "iso_name": "CentOS-6.4-x86_64-minimal.iso",
         "http_directory": "http",
         "local_ip": "10.80.3.223",