diff --git a/doc/config-reference/block-storage/drivers/hp-lefthand-driver.xml b/doc/config-reference/block-storage/drivers/hp-lefthand-driver.xml
index 6b935fbd0e..060c206ec6 100644
--- a/doc/config-reference/block-storage/drivers/hp-lefthand-driver.xml
+++ b/doc/config-reference/block-storage/drivers/hp-lefthand-driver.xml
@@ -257,6 +257,14 @@ hplefthand_iscsi_chap_enabled=false
 
 # Enable HTTP debugging to LeftHand (default=false)
 hplefthand_debug=false
+
+# The ratio of oversubscription when thin provisioned volumes are involved.
+# Default ratio is 20.0, this means that a provisioned capacity can be 20 times of the total
+# physical capacity.
+max_over_subscription_ratio=20.0
+
+# This flag represents the percentage of reserved back-end capacity.
+reserved_percentage=15
                     </programlisting>
                     <para>You can enable only one driver on each
                         cinder instance unless you enable multiple