diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java
index 52425211dc688..6c9ab586b0e25 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java
@@ -3241,8 +3241,32 @@ public AclStatus getAclStatus(Path path) throws IOException {
    */
   public void setXAttr(Path path, String name, byte[] value)
       throws IOException {
-    setXAttr(path, name, value, EnumSet.of(XAttrSetFlag.CREATE,
-        XAttrSetFlag.REPLACE));
+    setXAttr(path, name, value, false);
+  }
+
+  /**
+   * Set an xattr of a file or directory.
+   * The name must be prefixed with the namespace followed by ".". For example,
+   * "user.attr".
+   * <p>
+   * Refer to the HDFS extended attributes user documentation for details.
+   *
+   * @param path Path to modify
+   * @param name xattr name.
+   * @param value xattr value.
+   * @param enumValue if value is enumerable
+   * @throws IOException IO failure
+   * @throws UnsupportedOperationException if the operation is unsupported
+   *         (default outcome).
+   */
+  public void setXAttr(Path path, String name, byte[] value, boolean enumValue)
+          throws IOException {
+    EnumSet<XAttrSetFlag> flags = EnumSet.of(XAttrSetFlag.CREATE,
+            XAttrSetFlag.REPLACE);
+    if (enumValue) {
+      flags.add(XAttrSetFlag.ENUM_VALUE);
+    }
+    setXAttr(path, name, value, flags);
   }
 
   /**
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FilterFileSystem.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FilterFileSystem.java
index cdbe51e330701..14c5cdae713f6 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FilterFileSystem.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FilterFileSystem.java
@@ -626,6 +626,12 @@ public void setXAttr(Path path, String name, byte[] value)
     fs.setXAttr(path, name, value);
   }
 
+  @Override
+  public void setXAttr(Path path, String name, byte[] value, boolean numerable)
+      throws IOException {
+    fs.setXAttr(path, name, value, numerable);
+  }
+
   @Override
   public void setXAttr(Path path, String name, byte[] value,
       EnumSet<XAttrSetFlag> flag) throws IOException {
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/XAttrSetFlag.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/XAttrSetFlag.java
index 345a3d81e2c29..55e3dd4b954fd 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/XAttrSetFlag.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/XAttrSetFlag.java
@@ -38,7 +38,13 @@ public enum XAttrSetFlag {
    * Replace a existing xattr.
    * If the xattr does not exist, exception will be thrown.
    */
-  REPLACE((short) 0x02);
+  REPLACE((short) 0x02),
+
+  /**
+   * Value is enumerable.
+   * Value will be stored efficiently.
+   */
+  ENUM_VALUE((short) 0x04);
 
   private final short flag;
 
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/XAttrCommands.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/XAttrCommands.java
index 1d6eb28c9b1b5..b37b80b56080a 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/XAttrCommands.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/XAttrCommands.java
@@ -133,30 +133,38 @@ private void printXAttr(String name, byte[] value) throws IOException{
    */
   public static class SetfattrCommand extends FsCommand {
     public static final String NAME = SET_FATTR;
-    public static final String USAGE = "{-n name [-v value] | -x name} <path>";
+    public static final String USAGE = "{-n name [-v value [-e]] | -x name} <path>";
     public static final String DESCRIPTION =
-      "Sets an extended attribute name and value for a file or directory.\n" +
-      "-n name: The extended attribute name.\n" +
-      "-v value: The extended attribute value. There are three different " +
-      "encoding methods for the value. If the argument is enclosed in double " +
-      "quotes, then the value is the string inside the quotes. If the " +
-      "argument is prefixed with 0x or 0X, then it is taken as a hexadecimal " +
-      "number. If the argument begins with 0s or 0S, then it is taken as a " +
-      "base64 encoding.\n" +
-      "-x name: Remove the extended attribute.\n" +
-      "<path>: The file or directory.\n";
+        "Sets an extended attribute name and value for a file or directory.\n" +
+        "-n name: The extended attribute name.\n" +
+        "-v value: The extended attribute value. There are three different " +
+        "encoding methods for the value. If the argument is enclosed in double " +
+        "quotes, then the value is the string inside the quotes. If the " +
+        "argument is prefixed with 0x or 0X, then it is taken as a hexadecimal " +
+        "number. If the argument begins with 0s or 0S, then it is taken as a " +
+        "base64 encoding.\n" +
+        "-e: if set, means the value is enumerable, HDFS will try to store it " +
+        "efficiently.\n" +
+        "-x name: Remove the extended attribute.\n" +
+        "<path>: The file or directory.\n";
 
     private String name = null;
     private byte[] value = null;
     private String xname = null;
+    private boolean enumValue = false;
 
     @Override
     protected void processOptions(LinkedList<String> args) throws IOException {
       name = StringUtils.popOptionWithArgument("-n", args);
       String v = StringUtils.popOptionWithArgument("-v", args);
+      enumValue = StringUtils.popOption("-e", args);
       if (v != null) {
         value = XAttrCodec.decodeValue(v);
       }
+      if (enumValue && v == null) {
+        throw new HadoopIllegalArgumentException(
+                "Can not specify '-e' when '-v' is empty.");
+      }
       xname = StringUtils.popOptionWithArgument("-x", args);
 
       if (name != null && xname != null) {
@@ -179,7 +187,7 @@ protected void processOptions(LinkedList<String> args) throws IOException {
     @Override
     protected void processPath(PathData item) throws IOException {
       if (name != null) {
-        item.fs.setXAttr(item.path, name, value);
+        item.fs.setXAttr(item.path, name, value, enumValue);
       } else if (xname != null) {
         item.fs.removeXAttr(item.path, xname);
       }
diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestHarFileSystem.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestHarFileSystem.java
index b227e16908828..6442dfae16aa9 100644
--- a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestHarFileSystem.java
+++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestHarFileSystem.java
@@ -198,6 +198,9 @@ public void removeAclEntries(Path path, List<AclEntry> aclSpec)
     public void setXAttr(Path path, String name, byte[] value)
         throws IOException;
 
+    void setXAttr(Path path, String name, byte[] value, boolean numerable)
+        throws IOException;
+
     public void setXAttr(Path path, String name, byte[] value,
         EnumSet<XAttrSetFlag> flag) throws IOException;
 
diff --git a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/fs/XAttr.java b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/fs/XAttr.java
index a06ff0a508201..428935b004c04 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/fs/XAttr.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/fs/XAttr.java
@@ -68,11 +68,13 @@ public enum NameSpace {
   private final NameSpace ns;
   private final String name;
   private final byte[] value;
+  private final boolean enumerable;
 
   public static class Builder {
     private NameSpace ns = NameSpace.USER;
     private String name;
     private byte[] value;
+    private boolean numerable;
 
     public Builder setNameSpace(NameSpace ns) {
       this.ns = ns;
@@ -89,15 +91,21 @@ public Builder setValue(byte[] value) {
       return this;
     }
 
+    public Builder setEnumerable(boolean isNumerable) {
+      this.numerable = isNumerable;
+      return this;
+    }
+
     public XAttr build() {
-      return new XAttr(ns, name, value);
+      return new XAttr(ns, name, value, numerable);
     }
   }
 
-  private XAttr(NameSpace ns, String name, byte[] value) {
+  private XAttr(NameSpace ns, String name, byte[] value, boolean enumerable) {
     this.ns = ns;
     this.name = name;
     this.value = value;
+    this.enumerable = enumerable;
   }
 
   public NameSpace getNameSpace() {
@@ -112,12 +120,17 @@ public byte[] getValue() {
     return value;
   }
 
+  public boolean isEnumerable() {
+    return enumerable;
+  }
+
   @Override
   public int hashCode() {
     return new HashCodeBuilder(811, 67)
         .append(name)
         .append(ns)
         .append(value)
+        .append(enumerable)
         .toHashCode();
   }
 
@@ -133,6 +146,7 @@ public boolean equals(Object obj) {
         .append(ns, rhs.ns)
         .append(name, rhs.name)
         .append(value, rhs.value)
+        .append(enumerable, rhs.enumerable)
         .isEquals();
   }
 
@@ -152,12 +166,13 @@ public boolean equalsIgnoreValue(Object obj) {
     return new EqualsBuilder()
         .append(ns, rhs.ns)
         .append(name, rhs.name)
+        .append(isEnumerable(), rhs.isEnumerable())
         .isEquals();
   }
 
   @Override
   public String toString() {
-    return "XAttr [ns=" + ns + ", name=" + name + ", value="
+    return "XAttr [ns=" + ns + ", name=" + name + ", enumerable-" + enumerable + ", value="
         + Arrays.toString(value) + "]";
   }
 }
diff --git a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSClient.java b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSClient.java
index 116ed41703858..559b44165dedc 100755
--- a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSClient.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSClient.java
@@ -2906,7 +2906,7 @@ public void setXAttr(String src, String name, byte[] value,
       EnumSet<XAttrSetFlag> flag) throws IOException {
     checkOpen();
     try (TraceScope ignored = newPathTraceScope("setXAttr", src)) {
-      namenode.setXAttr(src, XAttrHelper.buildXAttr(name, value), flag);
+      namenode.setXAttr(src, XAttrHelper.buildXAttr(name, value, flag), flag);
     } catch (RemoteException re) {
       throw re.unwrapRemoteException(AccessControlException.class,
           FileNotFoundException.class,
diff --git a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/XAttrHelper.java b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/XAttrHelper.java
index 7e8812fc13f9b..8ad30ca290f39 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/XAttrHelper.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/XAttrHelper.java
@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.hdfs;
 
+import java.util.EnumSet;
 import java.util.List;
 import java.util.Map;
 
@@ -24,6 +25,7 @@
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.fs.XAttr;
 import org.apache.hadoop.fs.XAttr.NameSpace;
+import org.apache.hadoop.fs.XAttrSetFlag;
 import org.apache.hadoop.util.Lists;
 import org.apache.hadoop.util.StringUtils;
 
@@ -47,6 +49,10 @@ public static XAttr buildXAttr(String name) {
    * Both name and namespace are case sensitive.
    */
   public static XAttr buildXAttr(String name, byte[] value) {
+    return buildXAttr(name, value, null);
+  }
+
+  public static XAttr buildXAttr(String name, byte[] value, final EnumSet<XAttrSetFlag> flag) {
     Preconditions.checkNotNull(name, "XAttr name cannot be null.");
 
     final int prefixIndex = name.indexOf(".");
@@ -78,8 +84,13 @@ public static XAttr buildXAttr(String name, byte[] value) {
           "prefixed with user/trusted/security/system/raw, followed by a '.'");
     }
 
+    boolean isNumerable = false;
+    if (flag != null && flag.contains(XAttrSetFlag.ENUM_VALUE)) {
+      isNumerable = true;
+    }
+
     return (new XAttr.Builder()).setNameSpace(ns).setName(name.
-        substring(prefixIndex + 1)).setValue(value).build();
+        substring(prefixIndex + 1)).setValue(value).setEnumerable(isNumerable).build();
   }
 
   /**
diff --git a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelperClient.java b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelperClient.java
index 496a5cf46146d..320459301d4c5 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelperClient.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelperClient.java
@@ -1106,6 +1106,9 @@ public static XAttrProto convertXAttrProto(XAttr a) {
     if (a.getValue() != null) {
       builder.setValue(getByteString(a.getValue()));
     }
+    if (a.isEnumerable()) {
+      builder.setEnumerable(true);
+    }
     return builder.build();
   }
 
@@ -1353,6 +1356,9 @@ public static int convert(EnumSet<XAttrSetFlag> flag) {
     if (flag.contains(XAttrSetFlag.REPLACE)) {
       value |= XAttrSetFlagProto.XATTR_REPLACE.getNumber();
     }
+    if (flag.contains(XAttrSetFlag.ENUM_VALUE)) {
+      value |= XAttrSetFlagProto.XATTR_ENUMERABLE.getNumber();
+    }
     return value;
   }
 
@@ -2929,6 +2935,10 @@ public static EnumSet<XAttrSetFlag> convert(int flag) {
         XAttrSetFlagProto.XATTR_REPLACE_VALUE) {
       result.add(XAttrSetFlag.REPLACE);
     }
+    if ((flag & XAttrSetFlagProto.XATTR_ENUMERABLE.getNumber()) ==
+        XAttrSetFlagProto.XATTR_ENUMERABLE.getNumber()) {
+      result.add(XAttrSetFlag.ENUM_VALUE);
+    }
     return result;
   }
 
@@ -2941,6 +2951,9 @@ public static XAttr convertXAttr(XAttrProto a) {
     if (a.hasValue()) {
       builder.setValue(a.getValue().toByteArray());
     }
+    if (a.hasEnumerable()) {
+      builder.setEnumerable(a.getEnumerable());
+    }
     return builder.build();
   }
 
diff --git a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/proto/xattr.proto b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/proto/xattr.proto
index a53aa86c16dc8..74698900f48f5 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/proto/xattr.proto
+++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/proto/xattr.proto
@@ -33,11 +33,13 @@ message XAttrProto {
   required XAttrNamespaceProto namespace = 1;
   required string name = 2;
   optional bytes value = 3;
+  optional bool enumerable = 4;
 }
   
 enum XAttrSetFlagProto {
   XATTR_CREATE     = 0x01;
   XATTR_REPLACE    = 0x02;
+  XATTR_ENUMERABLE = 0x04;
 }
 
 message SetXAttrRequestProto {
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogOp.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogOp.java
index c8e0cd224e1af..3c877e990d7d9 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogOp.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogOp.java
@@ -5587,6 +5587,10 @@ private static void appendXAttrsToXml(ContentHandler contentHandler,
       XMLUtils.addSaxString(contentHandler, "NAMESPACE",
           xAttr.getNameSpace().toString());
       XMLUtils.addSaxString(contentHandler, "NAME", xAttr.getName());
+      if (xAttr.isEnumerable()) {
+        XMLUtils.addSaxString(contentHandler, "NUMERABLE",
+            String.valueOf(xAttr.isEnumerable()));
+      }
       if (xAttr.getValue() != null) {
         try {
           XMLUtils.addSaxString(contentHandler, "VALUE",
@@ -5610,7 +5614,8 @@ private static List<XAttr> readXAttrsFromXml(Stanza st)
     for (Stanza a: stanzas) {
       XAttr.Builder builder = new XAttr.Builder();
       builder.setNameSpace(XAttr.NameSpace.valueOf(a.getValue("NAMESPACE"))).
-          setName(a.getValue("NAME"));
+          setName(a.getValue("NAME")).
+          setEnumerable(Boolean.parseBoolean(a.getValueOrNull("NUMERABLE")));
       String v = a.getValueOrNull("VALUE");
       if (v != null) {
         try {
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSImageFormatPBINode.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSImageFormatPBINode.java
index 1f21871ac7b02..6cdbeeb3e9ac0 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSImageFormatPBINode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSImageFormatPBINode.java
@@ -92,6 +92,9 @@ public final class FSImageFormatPBINode {
   /* See the comments in fsimage.proto for an explanation of the following. */
   public static final int XATTR_NAMESPACE_EXT_OFFSET = 5;
   public static final int XATTR_NAMESPACE_EXT_MASK = 1;
+  public static final int XATTR_NUMERABLE_OFFSET = 4;
+  public static final int XATTR_NUMERABLE_MASK = 1;
+  public static final int XATTR_VALUE_MASK = (1 << 24) - 1;
 
   private static final Logger LOG =
       LoggerFactory.getLogger(FSImageFormatPBINode.class);
@@ -121,10 +124,16 @@ public static List<XAttr> loadXAttrs(
       for (XAttrCompactProto xAttrCompactProto : proto.getXAttrsList()) {
         int v = xAttrCompactProto.getName();
         byte[] value = null;
-        if (xAttrCompactProto.getValue() != null) {
-          value = xAttrCompactProto.getValue().toByteArray();
+        if (XAttrFormat.isNumerable(v)) {
+          assert xAttrCompactProto.hasValueInt();
+          int valueInt = xAttrCompactProto.getValueInt();
+          b.add(XAttrFormat.toXAttr(v, valueInt, stringTable));
+        } else {
+          if (xAttrCompactProto.getValue() != null) {
+            value = xAttrCompactProto.getValue().toByteArray();
+          }
+          b.add(XAttrFormat.toXAttr(v, value, stringTable));
         }
-        b.add(XAttrFormat.toXAttr(v, value, stringTable));
       }
       
       return b;
@@ -648,8 +657,12 @@ private static XAttrFeatureProto.Builder buildXAttrs(XAttrFeature f) {
             newBuilder();
         int v = XAttrFormat.toInt(a);
         xAttrCompactBuilder.setName(v);
-        if (a.getValue() != null) {
-          xAttrCompactBuilder.setValue(PBHelperClient.getByteString(a.getValue()));
+        if (a.isEnumerable()) {
+          xAttrCompactBuilder.setValueInt(XAttrValueFormat.toInt(a.getValue()));
+        } else {
+          if (a.getValue() != null) {
+            xAttrCompactBuilder.setValue(PBHelperClient.getByteString(a.getValue()));
+          }
         }
         b.addXAttrs(xAttrCompactBuilder.build());
       }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.java
index 61fdd7d5b3e18..78c5a18213146 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.java
@@ -30,7 +30,7 @@ public enum SerialNumberManager {
   GLOBAL(),
   USER(PermissionStatusFormat.USER, AclEntryStatusFormat.NAME),
   GROUP(PermissionStatusFormat.GROUP, AclEntryStatusFormat.NAME),
-  XATTR(XAttrFormat.NAME);
+  XATTR(XAttrFormat.NAME, XAttrValueFormat.VALUE);
 
   private static final SerialNumberManager[] values = values();
   private static final int maxEntryBits;
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrFeature.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrFeature.java
index 11263bb9a01e2..ddd8e2f7092cc 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrFeature.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrFeature.java
@@ -50,7 +50,8 @@ public XAttrFeature(List<XAttr> xAttrs) {
       ImmutableList.Builder<XAttr> b = null;
       for (XAttr attr : xAttrs) {
         if (attr.getValue() == null ||
-            attr.getValue().length <= PACK_THRESHOLD) {
+            attr.getValue().length <= PACK_THRESHOLD ||
+            attr.isEnumerable()) {
           toPack.add(attr);
         } else {
           if (b == null) {
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrFormat.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrFormat.java
index 4d46e691df217..f53035ae270b7 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrFormat.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrFormat.java
@@ -19,6 +19,7 @@
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -36,10 +37,11 @@
  * incompatible.
  *
  */
-
+@SuppressWarnings("checkstyle:MemberName")
 public enum XAttrFormat implements LongBitFormat.Enum {
-  RESERVED(null, 5),
-  NS_EXT(RESERVED.BITS, 1),
+  RESERVED(null, 4),
+  NUMERABLE(RESERVED.BITS, 1),
+  NS_EXT(NUMERABLE.BITS, 1),
   NAME(NS_EXT.BITS, 24),
   NS(NAME.BITS, 2);
 
@@ -72,17 +74,23 @@ public static String getName(int record) {
     return SerialNumberManager.XATTR.getString(nid);
   }
 
+  public static boolean isNumerable(int record) {
+    return (int)NUMERABLE.BITS.retrieve(record) == 1;
+  }
+
   static int toInt(XAttr a) {
     int nid = SerialNumberManager.XATTR.getSerialNumber(a.getName());
     int nsOrd = a.getNameSpace().ordinal();
     long value = NS.BITS.combine(nsOrd & NS_MASK, 0L);
     value = NS_EXT.BITS.combine(nsOrd >>> NS_EXT_SHIFT, value);
     value = NAME.BITS.combine(nid, value);
+    value = NUMERABLE.BITS.combine(a.isEnumerable() ? 1 : 0, value);
     return (int)value;
   }
 
   static XAttr toXAttr(int record, byte[] value,
                        SerialNumberManager.StringTable stringTable) {
+    assert NUMERABLE.BITS.retrieve(record) == 0;
     int nid = (int)NAME.BITS.retrieve(record);
     String name = SerialNumberManager.XATTR.getString(nid, stringTable);
     return new XAttr.Builder()
@@ -92,6 +100,18 @@ static XAttr toXAttr(int record, byte[] value,
         .build();
   }
 
+  static XAttr toXAttr(int record, int valueInt,
+                       SerialNumberManager.StringTable stringTable) {
+    assert NUMERABLE.BITS.retrieve(record) == 1;
+    int nid = (int)NAME.BITS.retrieve(record);
+    String name = SerialNumberManager.XATTR.getString(nid, stringTable);
+    return new XAttr.Builder()
+            .setNameSpace(getNamespace(record))
+            .setName(name)
+            .setValue(XAttrValueFormat.getValue(valueInt))
+            .build();
+  }
+
   /**
    * Unpack byte[] to XAttrs.
    * 
@@ -111,13 +131,23 @@ static List<XAttr> toXAttrs(byte[] attrs) {
       i += 4;
       builder.setNameSpace(XAttrFormat.getNamespace(v));
       builder.setName(XAttrFormat.getName(v));
-      int vlen = ((0xff & attrs[i]) << 8) | (0xff & attrs[i + 1]);
-      i += 2;
-      if (vlen > 0) {
-        byte[] value = new byte[vlen];
-        System.arraycopy(attrs, i, value, 0, vlen);
-        builder.setValue(value);
-        i += vlen;
+      boolean isEnumerable = XAttrFormat.isNumerable(v);
+      builder.setEnumerable(isEnumerable);
+      if (!isEnumerable) {
+        int vlen = ((0xff & attrs[i]) << 8) | (0xff & attrs[i + 1]);
+        i += 2;
+        if (vlen > 0) {
+          byte[] value = new byte[vlen];
+          System.arraycopy(attrs, i, value, 0, vlen);
+          builder.setValue(value);
+          i += vlen;
+        }
+      } else {
+        // big-endian
+        v = Ints.fromBytes(attrs[i], attrs[i + 1],
+                attrs[i + 2], attrs[i + 3]);
+        i += 4;
+        builder.setValue(XAttrValueFormat.getValue(v));
       }
       xAttrs.add(builder.build());
     }
@@ -145,19 +175,40 @@ static XAttr getXAttr(byte[] attrs, String prefixedName) {
       i += 4;
       XAttr.NameSpace namespace = XAttrFormat.getNamespace(v);
       String name = XAttrFormat.getName(v);
-      int vlen = ((0xff & attrs[i]) << 8) | (0xff & attrs[i + 1]);
-      i += 2;
+      boolean isEnumerable = XAttrFormat.isNumerable(v);
+      // If enumerable, tmpInt is int for XAttrValueFormat
+      // It not enumerable, tmpInt is for vlen
+      int tmpInt;
+      if (isEnumerable) {
+        // big-endian
+        tmpInt = Ints.fromBytes(attrs[i], attrs[i + 1],
+                attrs[i + 2], attrs[i + 3]);
+        i += 4;
+      } else {
+        tmpInt = ((0xff & attrs[i]) << 8) | (0xff & attrs[i + 1]);
+        i += 2;
+      }
       if (xAttr.getNameSpace() == namespace &&
-          xAttr.getName().equals(name)) {
-        if (vlen > 0) {
-          byte[] value = new byte[vlen];
-          System.arraycopy(attrs, i, value, 0, vlen);
+              xAttr.getName().equals(name)) {
+        if (isEnumerable) {
           return new XAttr.Builder().setNameSpace(namespace).
-              setName(name).setValue(value).build();
+                  setName(name).
+                  setValue(XAttrValueFormat.getValue(tmpInt)).
+                  build();
+        } else {
+          if (tmpInt > 0) {
+            byte[] value = new byte[tmpInt];
+            System.arraycopy(attrs, i, value, 0, tmpInt);
+            return new XAttr.Builder().setNameSpace(namespace).
+                    setName(name).setValue(value).build();
+          }
+          return xAttr;
+        }
+      } else {
+        if (!isEnumerable) {
+          i += tmpInt;
         }
-        return xAttr;
       }
-      i += vlen;
     }
     return null;
   }
@@ -178,13 +229,19 @@ static byte[] toBytes(List<XAttr> xAttrs) {
         // big-endian
         int v = XAttrFormat.toInt(a);
         out.write(Ints.toByteArray(v));
-        int vlen = a.getValue() == null ? 0 : a.getValue().length;
-        Preconditions.checkArgument(vlen < XATTR_VALUE_LEN_MAX,
-            "The length of xAttr values is too long.");
-        out.write((byte)(vlen >> 8));
-        out.write((byte)(vlen));
-        if (vlen > 0) {
-          out.write(a.getValue());
+        if (!a.isEnumerable()) {
+          int vlen = a.getValue() == null ? 0 : a.getValue().length;
+          Preconditions.checkArgument(vlen < XATTR_VALUE_LEN_MAX,
+                  "The length of xAttr values is too long.");
+          out.write((byte) (vlen >> 8));
+          out.write((byte) (vlen));
+          if (vlen > 0) {
+            out.write(a.getValue());
+          }
+        } else {
+          out.write(Ints.toByteArray(
+              SerialNumberManager.XATTR.getSerialNumber(
+                  new String(a.getValue(), StandardCharsets.UTF_8))));
         }
       }
     } catch (IOException e) {
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrValueFormat.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrValueFormat.java
new file mode 100644
index 0000000000000..3fb61322fee89
--- /dev/null
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/XAttrValueFormat.java
@@ -0,0 +1,58 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode;
+
+import org.apache.hadoop.hdfs.util.LongBitFormat;
+
+import java.nio.charset.StandardCharsets;
+
+/**
+ * Class to pack XAttrs Value.<br>
+ *
+ * Note:  this format is used both in-memory and on-disk.  Changes will be
+ * incompatible.
+ *
+ */
+
+public enum XAttrValueFormat implements LongBitFormat.Enum {
+  VALUE(null, 24);
+
+  private final LongBitFormat BITS;
+
+  XAttrValueFormat(LongBitFormat previous, int length) {
+    BITS = new LongBitFormat(name(), previous, length, 0);
+  }
+
+  @Override
+  public int getLength() {
+    return BITS.getLength();
+  }
+
+  public static byte[] getValue(int record) {
+    int nid = (int)VALUE.BITS.retrieve(record);
+    return SerialNumberManager.XATTR.getString(nid).getBytes(StandardCharsets.UTF_8);
+  }
+
+  static int toInt(byte[] value) {
+    int vid = SerialNumberManager.XATTR.getSerialNumber(new String(value, StandardCharsets.UTF_8));
+    long res = 0L;
+    res = VALUE.BITS.combine(vid, res);
+    return (int)res;
+  }
+
+}
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/OfflineImageReconstructor.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/OfflineImageReconstructor.java
index 6a2049acb4b54..e79058874ad19 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/OfflineImageReconstructor.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/OfflineImageReconstructor.java
@@ -18,15 +18,8 @@
 package org.apache.hadoop.hdfs.tools.offlineImageViewer;
 
 import org.apache.hadoop.util.Preconditions;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.ACL_ENTRY_NAME_MASK;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.ACL_ENTRY_NAME_OFFSET;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.ACL_ENTRY_SCOPE_OFFSET;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.ACL_ENTRY_TYPE_OFFSET;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAMESPACE_MASK;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAME_OFFSET;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAMESPACE_OFFSET;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAMESPACE_EXT_OFFSET;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAMESPACE_EXT_MASK;
+
+import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.*;
 import static org.apache.hadoop.hdfs.tools.offlineImageViewer.PBImageXmlWriter.*;
 
 import java.io.BufferedOutputStream;
@@ -891,18 +884,25 @@ private INodeSection.XAttrFeatureProto.Builder xattrsXmlToProto(Node xattrs)
       int nsIdx = XAttrProtos.XAttrProto.
           XAttrNamespaceProto.valueOf(ns).ordinal();
       String name = xattr.removeChildStr(SECTION_NAME);
-      String valStr = xattr.removeChildStr(INODE_SECTION_VAL);
-      byte[] val = null;
-      if (valStr == null) {
-        String valHex = xattr.removeChildStr(INODE_SECTION_VAL_HEX);
-        if (valHex == null) {
-          throw new IOException("<xattr> had no <val> or <valHex> entry.");
-        }
-        val = new HexBinaryAdapter().unmarshal(valHex);
+      boolean numerable = xattr.removeChildBool(INODE_SECTION_NUMERABLE);
+      if (numerable) {
+        String valStr = xattr.removeChildStr(INODE_SECTION_VAL);
+        int valueId = registerStringId(valStr);
+        b.setValueInt(valueId);
       } else {
-        val = valStr.getBytes("UTF8");
+        String valStr = xattr.removeChildStr(INODE_SECTION_VAL);
+        byte[] val = null;
+        if (valStr == null) {
+          String valHex = xattr.removeChildStr(INODE_SECTION_VAL_HEX);
+          if (valHex == null) {
+            throw new IOException("<xattr> had no <val> or <valHex> entry.");
+          }
+          val = new HexBinaryAdapter().unmarshal(valHex);
+        } else {
+          val = valStr.getBytes("UTF8");
+        }
+        b.setValue(ByteString.copyFrom(val));
       }
-      b.setValue(ByteString.copyFrom(val));
 
       // The XAttrCompactProto name field uses a fairly complex format
       // to encode both the string table ID of the xattr name and the
@@ -911,7 +911,8 @@ private INodeSection.XAttrFeatureProto.Builder xattrsXmlToProto(Node xattrs)
       int encodedName = (nameId << XATTR_NAME_OFFSET) |
           ((nsIdx & XATTR_NAMESPACE_MASK) << XATTR_NAMESPACE_OFFSET) |
           (((nsIdx >> 2) & XATTR_NAMESPACE_EXT_MASK)
-              << XATTR_NAMESPACE_EXT_OFFSET);
+              << XATTR_NAMESPACE_EXT_OFFSET) |
+          (numerable ? 1 : 0) << XATTR_NUMERABLE_OFFSET;
       b.setName(encodedName);
       xattr.verifyNoRemainingKeys("xattr");
       bld.addXAttrs(b);
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/PBImageXmlWriter.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/PBImageXmlWriter.java
index 8030ead8b5212..93bc52fcc4557 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/PBImageXmlWriter.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/PBImageXmlWriter.java
@@ -73,12 +73,7 @@
 import org.apache.hadoop.thirdparty.com.google.common.collect.ImmutableList;
 import org.apache.hadoop.thirdparty.protobuf.ByteString;
 
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAMESPACE_MASK;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAMESPACE_OFFSET;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAMESPACE_EXT_MASK;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAMESPACE_EXT_OFFSET;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAME_OFFSET;
-import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.XATTR_NAME_MASK;
+import static org.apache.hadoop.hdfs.server.namenode.FSImageFormatPBINode.*;
 
 /**
  * PBImageXmlWriter walks over an fsimage structure and writes out
@@ -177,6 +172,7 @@ public final class PBImageXmlWriter {
   public static final String INODE_SECTION_QUOTA = "quota";
   public static final String INODE_SECTION_TARGET = "target";
   public static final String INODE_SECTION_NS = "ns";
+  public static final String INODE_SECTION_NUMERABLE = "numerable";
   public static final String INODE_SECTION_VAL = "val";
   public static final String INODE_SECTION_VAL_HEX = "valHex";
   public static final String INODE_SECTION_INODE = "inode";
@@ -438,11 +434,19 @@ private void dumpXattrs(INodeSection.XAttrFeatureProto xattrs) {
       o(SECTION_NAME, SerialNumberManager.XATTR.getString(
           XATTR_NAME_MASK & (encodedName >> XATTR_NAME_OFFSET),
           stringTable));
-      ByteString val = xattr.getValue();
-      if (val.isValidUtf8()) {
-        o(INODE_SECTION_VAL, val.toStringUtf8());
+      boolean numerable = (XATTR_NUMERABLE_MASK & (encodedName >> XATTR_NUMERABLE_OFFSET)) == 1;
+      o(INODE_SECTION_NUMERABLE, numerable);
+      if (numerable) {
+        int valueInt = xattr.getValueInt();
+        o(INODE_SECTION_VAL, SerialNumberManager.XATTR.getString(XATTR_VALUE_MASK & valueInt,
+            stringTable));
       } else {
-        o(INODE_SECTION_VAL_HEX, Hex.encodeHexString(val.toByteArray()));
+        ByteString val = xattr.getValue();
+        if (val.isValidUtf8()) {
+          o(INODE_SECTION_VAL, val.toStringUtf8());
+        } else {
+          o(INODE_SECTION_VAL_HEX, Hex.encodeHexString(val.toByteArray()));
+        }
       }
       out.print("</" + INODE_SECTION_XATTR + ">");
     }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/proto/fsimage.proto b/hadoop-hdfs-project/hadoop-hdfs/src/main/proto/fsimage.proto
index 2bdd302a1e4ef..d9b56513fc506 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/proto/fsimage.proto
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/proto/fsimage.proto
@@ -119,10 +119,12 @@ message INodeSection {
      * so only 2 bits were needed. At that time, this bit was reserved. When a
      * 5th namespace was created (raw) this bit became used as a 3rd namespace
      * bit.
-     * [27:32) -- reserved for future uses.
+     * [27:28) -- indicating if the value is enumerable
+     * [28:32) -- reserved for future uses.
      */
     required fixed32 name = 1;
     optional bytes value = 2;
+    optional fixed32 valueInt = 3;
   }
   
   message XAttrFeatureProto {
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/TestOfflineImageViewer.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/TestOfflineImageViewer.java
index b4ba775732921..1d1116c384e7b 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/TestOfflineImageViewer.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/TestOfflineImageViewer.java
@@ -321,6 +321,8 @@ public static void createOriginalFSImage() throws IOException {
       // OIV should be able to handle XAttr values that can't be expressed
       // as UTF8
       hdfs.setXAttr(xattr, "user.a4", new byte[]{ -0x3d, 0x28 });
+      // Set enumerable attribute
+      hdfs.setXAttr(xattr, "user.a5", new byte[]{0x37, 0x38, 0x39}, true);
       writtenFiles.put(xattr.toString(), hdfs.getFileStatus(xattr));
       // Set ACLs
       hdfs.setAcl(