diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/StorageType.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/StorageType.java
index 68069d7256..0948801a59 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/StorageType.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/StorageType.java
@@ -33,10 +33,11 @@
 @InterfaceAudience.Public
 @InterfaceStability.Unstable
 public enum StorageType {
-  DISK(false),
+  // sorted by the speed of the storage types, from fast to slow
+  RAM_DISK(true),
   SSD(false),
-  ARCHIVE(false),
-  RAM_DISK(true);
+  DISK(false),
+  ARCHIVE(false);
 
   private final boolean isTransient;
 
diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 9822575877..79e7820e87 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -920,6 +920,8 @@ Release 2.7.1 - UNRELEASED
     HDFS-8521. Add VisibleForTesting annotation to
     BlockPoolSlice#selectReplicaToDelete. (cmccabe)
 
+    HDFS-8361. Choose SSD over DISK in block placement.  (szetszwo)
+
   OPTIMIZATIONS
 
   BUG FIXES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockStoragePolicy.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockStoragePolicy.java
index ea69f976a6..0d59deda37 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockStoragePolicy.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestBlockStoragePolicy.java
@@ -26,6 +26,7 @@
 
 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
+
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.BlockStoragePolicySpi;
 import org.apache.hadoop.fs.FSDataOutputStream;
@@ -40,7 +41,7 @@
 import org.apache.hadoop.hdfs.server.datanode.DataNodeTestUtils;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotTestHelper;
-import org.apache.hadoop.io.IOUtils;
+import org.apache.hadoop.hdfs.server.protocol.DatanodeStorage;
 import org.apache.hadoop.ipc.RemoteException;
 import org.apache.hadoop.net.NetworkTopology;
 import org.apache.hadoop.net.Node;
@@ -1152,6 +1153,50 @@ public void testChooseTargetWithTopology() throws Exception {
     Assert.assertEquals(3, targets.length);
   }
 
+  @Test
+  public void testChooseSsdOverDisk() throws Exception {
+    BlockStoragePolicy policy = new BlockStoragePolicy((byte) 9, "TEST1",
+        new StorageType[]{StorageType.SSD, StorageType.DISK,
+            StorageType.ARCHIVE}, new StorageType[]{}, new StorageType[]{});
+
+    final String[] racks = {"/d1/r1", "/d1/r1", "/d1/r1"};
+    final String[] hosts = {"host1", "host2", "host3"};
+    final StorageType[] disks = {StorageType.DISK, StorageType.DISK, StorageType.DISK};
+
+    final DatanodeStorageInfo[] diskStorages
+        = DFSTestUtil.createDatanodeStorageInfos(3, racks, hosts, disks);
+    final DatanodeDescriptor[] dataNodes
+        = DFSTestUtil.toDatanodeDescriptor(diskStorages);
+    for(int i = 0; i < dataNodes.length; i++) {
+      BlockManagerTestUtil.updateStorage(dataNodes[i],
+          new DatanodeStorage("ssd" + i, DatanodeStorage.State.NORMAL,
+              StorageType.SSD));
+    }
+
+    FileSystem.setDefaultUri(conf, "hdfs://localhost:0");
+    conf.set(DFSConfigKeys.DFS_NAMENODE_HTTP_ADDRESS_KEY, "0.0.0.0:0");
+    File baseDir = PathUtils.getTestDir(TestReplicationPolicy.class);
+    conf.set(DFSConfigKeys.DFS_NAMENODE_NAME_DIR_KEY,
+        new File(baseDir, "name").getPath());
+    DFSTestUtil.formatNameNode(conf);
+    NameNode namenode = new NameNode(conf);
+
+    final BlockManager bm = namenode.getNamesystem().getBlockManager();
+    BlockPlacementPolicy replicator = bm.getBlockPlacementPolicy();
+    NetworkTopology cluster = bm.getDatanodeManager().getNetworkTopology();
+    for (DatanodeDescriptor datanode : dataNodes) {
+      cluster.add(datanode);
+    }
+
+    DatanodeStorageInfo[] targets = replicator.chooseTarget("/foo", 3,
+        dataNodes[0], Collections.<DatanodeStorageInfo>emptyList(), false,
+        new HashSet<Node>(), 0, policy);
+    System.out.println(policy.getName() + ": " + Arrays.asList(targets));
+    Assert.assertEquals(2, targets.length);
+    Assert.assertEquals(StorageType.SSD, targets[0].getStorageType());
+    Assert.assertEquals(StorageType.DISK, targets[1].getStorageType());
+  }
+
   @Test
   public void testGetFileStoragePolicyAfterRestartNN() throws Exception {
     //HDFS8219
@@ -1233,4 +1278,32 @@ public void testGetAllStoragePoliciesFromFs() throws IOException {
       cluster.shutdown();
     }
   }
+
+  @Test
+  public void testStorageType() {
+    final EnumMap<StorageType, Integer> map = new EnumMap<>(StorageType.class);
+
+    //put storage type is reversed order
+    map.put(StorageType.ARCHIVE, 1);
+    map.put(StorageType.DISK, 1);
+    map.put(StorageType.SSD, 1);
+    map.put(StorageType.RAM_DISK, 1);
+
+    {
+      final Iterator<StorageType> i = map.keySet().iterator();
+      Assert.assertEquals(StorageType.RAM_DISK, i.next());
+      Assert.assertEquals(StorageType.SSD, i.next());
+      Assert.assertEquals(StorageType.DISK, i.next());
+      Assert.assertEquals(StorageType.ARCHIVE, i.next());
+    }
+
+    {
+      final Iterator<Map.Entry<StorageType, Integer>> i
+          = map.entrySet().iterator();
+      Assert.assertEquals(StorageType.RAM_DISK, i.next().getKey());
+      Assert.assertEquals(StorageType.SSD, i.next().getKey());
+      Assert.assertEquals(StorageType.DISK, i.next().getKey());
+      Assert.assertEquals(StorageType.ARCHIVE, i.next().getKey());
+    }
+  }
 }