diff --git a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/server/protocol/DatanodeStorage.java b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/server/protocol/DatanodeStorage.java
index de4ff252dc0a5..e4042978356b7 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/server/protocol/DatanodeStorage.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/server/protocol/DatanodeStorage.java
@@ -24,7 +24,7 @@
 /**
  * Class captures information of a storage in Datanode.
  */
-public class DatanodeStorage {
+public class DatanodeStorage implements Comparable<DatanodeStorage> {
   /** The state of the storage. */
   public enum State {
     NORMAL,
@@ -125,4 +125,9 @@ public boolean equals(Object other){
   public int hashCode() {
     return getStorageID().hashCode();
   }
+
+  @Override
+  public int compareTo(DatanodeStorage that) {
+    return getStorageID().compareTo(that.getStorageID());
+  }
 }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BPServiceActor.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BPServiceActor.java
index b552fa277d049..dac42b59d5524 100755
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BPServiceActor.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BPServiceActor.java
@@ -412,7 +412,7 @@ List<DatanodeCommand> blockReport(long fullBrLeaseId) throws IOException {
     StorageBlockReport reports[] =
         new StorageBlockReport[perVolumeBlockLists.size()];
 
-    for(Map.Entry<DatanodeStorage, BlockListAsLongs> kvPair : perVolumeBlockLists.entrySet()) {
+    for (Map.Entry<DatanodeStorage, BlockListAsLongs> kvPair : perVolumeBlockLists.entrySet()) {
       BlockListAsLongs blockList = kvPair.getValue();
       reports[i++] = new StorageBlockReport(kvPair.getKey(), blockList);
       totalBlockCount += blockList.getNumberOfBlocks();
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java
index f1115efcc21dc..9740958eb69f9 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java
@@ -38,6 +38,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.TreeMap;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Executor;
 
@@ -2097,7 +2098,7 @@ public List<Long> getCacheReport(String bpid) {
   @Override
   public Map<DatanodeStorage, BlockListAsLongs> getBlockReports(String bpid) {
     Map<DatanodeStorage, BlockListAsLongs> blockReportsMap =
-        new HashMap<DatanodeStorage, BlockListAsLongs>();
+        new TreeMap<DatanodeStorage, BlockListAsLongs>();
 
     Map<String, BlockListAsLongs.Builder> builders =
         new HashMap<String, BlockListAsLongs.Builder>();
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/SimulatedFSDataset.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/SimulatedFSDataset.java
index 8c75ca9f75208..05e411f7e710b 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/SimulatedFSDataset.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/SimulatedFSDataset.java
@@ -26,7 +26,6 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -837,7 +836,8 @@ synchronized BlockListAsLongs getBlockReport(String bpid,
   @Override
   public synchronized Map<DatanodeStorage, BlockListAsLongs> getBlockReports(
       String bpid) {
-    Map<DatanodeStorage, BlockListAsLongs> blockReports = new HashMap<>();
+    Map<DatanodeStorage, BlockListAsLongs> blockReports =
+        new TreeMap<DatanodeStorage, BlockListAsLongs>();
     for (SimulatedStorage storage : storages) {
       blockReports.put(storage.getDnStorage(), getBlockReport(bpid, storage));
     }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/extdataset/ExternalDatasetImpl.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/extdataset/ExternalDatasetImpl.java
index 1bd42e0bdfbeb..11b604f1b1d03 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/extdataset/ExternalDatasetImpl.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/extdataset/ExternalDatasetImpl.java
@@ -194,8 +194,8 @@ public void unfinalizeBlock(ExtendedBlock b) throws IOException {
 
   @Override
   public Map<DatanodeStorage, BlockListAsLongs> getBlockReports(String bpid) {
-    final Map<DatanodeStorage, BlockListAsLongs> result =
-	new HashMap<DatanodeStorage, BlockListAsLongs>();
+    final Map<DatanodeStorage, BlockListAsLongs> result = 
+        new TreeMap<DatanodeStorage, BlockListAsLongs>();
 
     result.put(storage, BlockListAsLongs.EMPTY);
     return result;