diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 237e0a444fa..486bccbfd1a 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -1880,6 +1880,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-7452. skip StandbyException log for getCorruptFiles()
     (Bramha Reddy Battula via vinayakumarb)
 
+    HDFS-9842. dfs.datanode.balance.bandwidthPerSec should accept friendly
+    size units.  (Lin Yiqun via Arpit Agarwal)
+
 Release 2.7.3 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataXceiverServer.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataXceiverServer.java
index 36cf8a18077..8152e6ffb0e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataXceiverServer.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataXceiverServer.java
@@ -131,7 +131,7 @@ class DataXceiverServer implements Runnable {
     
     //set up parameter for cluster balancing
     this.balanceThrottler = new BlockBalanceThrottler(
-        conf.getLong(DFSConfigKeys.DFS_DATANODE_BALANCE_BANDWIDTHPERSEC_KEY,
+        conf.getLongBytes(DFSConfigKeys.DFS_DATANODE_BALANCE_BANDWIDTHPERSEC_KEY,
             DFSConfigKeys.DFS_DATANODE_BALANCE_BANDWIDTHPERSEC_DEFAULT),
         conf.getInt(DFSConfigKeys.DFS_DATANODE_BALANCE_MAX_NUM_CONCURRENT_MOVES_KEY,
             DFSConfigKeys.DFS_DATANODE_BALANCE_MAX_NUM_CONCURRENT_MOVES_DEFAULT));
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml b/hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml
index 32a771150d4..a250eb19410 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml
@@ -815,7 +815,11 @@
   <description>
         Specifies the maximum amount of bandwidth that each datanode
         can utilize for the balancing purpose in term of
-        the number of bytes per second.
+        the number of bytes per second. You can use the following
+        suffix (case insensitive):
+        k(kilo), m(mega), g(giga), t(tera), p(peta), e(exa)to specify the size
+        (such as 128k, 512m, 1g, etc.).
+        Or provide complete size in bytes (such as 134217728 for 128 MB).
   </description>
 </property>