diff --git a/hadoop-common-project/hadoop-common/CHANGES.HDFS-1623.txt b/hadoop-common-project/hadoop-common/CHANGES.HDFS-1623.txt
index 04db5dae38..56e11457c5 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.HDFS-1623.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.HDFS-1623.txt
@@ -13,3 +13,5 @@ HADOOP-7896. HA: if both NNs are in Standby mode, client needs to try failing
 
 HADOOP-7922. Improve some logging for client IPC failovers and
              StandbyExceptions (todd)
+
+HADOOP-7921. StandbyException should extend IOException (todd)
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/StandbyException.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/StandbyException.java
index 49f4fadfd5..7a168619af 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/StandbyException.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/StandbyException.java
@@ -17,6 +17,8 @@
  */
 package org.apache.hadoop.ipc;
 
+import java.io.IOException;
+
 import org.apache.hadoop.classification.InterfaceStability;
 
 /**
@@ -24,7 +26,7 @@
  * set of servers in which only a subset may be active.
  */
 @InterfaceStability.Evolving
-public class StandbyException extends Exception {
+public class StandbyException extends IOException {
   static final long serialVersionUID = 0x12308AD010L;
   public StandbyException(String msg) {
     super(msg);