diff --git a/core/src/main/java/org/elasticsearch/index/translog/TranslogStats.java b/core/src/main/java/org/elasticsearch/index/translog/TranslogStats.java
index e727a400c05..a4431b520cd 100644
--- a/core/src/main/java/org/elasticsearch/index/translog/TranslogStats.java
+++ b/core/src/main/java/org/elasticsearch/index/translog/TranslogStats.java
@@ -18,11 +18,10 @@
  */
 package org.elasticsearch.index.translog;
 
+import org.elasticsearch.action.support.ToXContentToBytes;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Streamable;
-import org.elasticsearch.common.unit.ByteSizeValue;
-import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentBuilderString;
 
@@ -31,17 +30,23 @@ import java.io.IOException;
 /**
  *
  */
-public class TranslogStats implements ToXContent, Streamable {
+public class TranslogStats extends ToXContentToBytes implements Streamable {
 
     private long translogSizeInBytes;
-    private int estimatedNumberOfOperations;
+    private int numberOfOperations;
 
     public TranslogStats() {
     }
 
-    public TranslogStats(int estimatedNumberOfOperations, long translogSizeInBytes) {
+    public TranslogStats(int numberOfOperations, long translogSizeInBytes) {
+        if (numberOfOperations < 0) {
+            throw new IllegalArgumentException("numberOfOperations must be >= 0");
+        }
+        if (translogSizeInBytes < 0) {
+            throw new IllegalArgumentException("translogSizeInBytes must be >= 0");
+        }
         assert translogSizeInBytes >= 0 : "translogSizeInBytes must be >= 0, got [" + translogSizeInBytes + "]";
-        this.estimatedNumberOfOperations = estimatedNumberOfOperations;
+        this.numberOfOperations = numberOfOperations;
         this.translogSizeInBytes = translogSizeInBytes;
     }
 
@@ -50,22 +55,22 @@ public class TranslogStats implements ToXContent, Streamable {
             return;
         }
 
-        this.estimatedNumberOfOperations += translogStats.estimatedNumberOfOperations;
-        this.translogSizeInBytes = +translogStats.translogSizeInBytes;
+        this.numberOfOperations += translogStats.numberOfOperations;
+        this.translogSizeInBytes += translogStats.translogSizeInBytes;
     }
 
-    public ByteSizeValue translogSizeInBytes() {
-        return new ByteSizeValue(translogSizeInBytes);
+    public long getTranslogSizeInBytes() {
+        return translogSizeInBytes;
     }
 
     public long estimatedNumberOfOperations() {
-        return estimatedNumberOfOperations;
+        return numberOfOperations;
     }
 
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject(Fields.TRANSLOG);
-        builder.field(Fields.OPERATIONS, estimatedNumberOfOperations);
+        builder.field(Fields.OPERATIONS, numberOfOperations);
         builder.byteSizeField(Fields.SIZE_IN_BYTES, Fields.SIZE, translogSizeInBytes);
         builder.endObject();
         return builder;
@@ -80,13 +85,13 @@ public class TranslogStats implements ToXContent, Streamable {
 
     @Override
     public void readFrom(StreamInput in) throws IOException {
-        estimatedNumberOfOperations = in.readVInt();
+        numberOfOperations = in.readVInt();
         translogSizeInBytes = in.readVLong();
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeVInt(estimatedNumberOfOperations);
+        out.writeVInt(numberOfOperations);
         out.writeVLong(translogSizeInBytes);
     }
 }
diff --git a/core/src/test/java/org/elasticsearch/index/engine/ShadowEngineTests.java b/core/src/test/java/org/elasticsearch/index/engine/ShadowEngineTests.java
index 4c132f34417..2c6ee40b86e 100644
--- a/core/src/test/java/org/elasticsearch/index/engine/ShadowEngineTests.java
+++ b/core/src/test/java/org/elasticsearch/index/engine/ShadowEngineTests.java
@@ -965,4 +965,13 @@ public class ShadowEngineTests extends ESTestCase {
         // (shadow engine is already shut down in the try-with-resources)
         IOUtils.close(srStore, pEngine, pStore);
     }
+
+    public void testNoTranslog() {
+        try {
+            replicaEngine.getTranslog();
+            fail("shadow engine has no translog");
+        } catch (UnsupportedOperationException ex) {
+            // all good
+        }
+    }
 }
diff --git a/core/src/test/java/org/elasticsearch/index/translog/TranslogTests.java b/core/src/test/java/org/elasticsearch/index/translog/TranslogTests.java
index e345e208c7d..5a25f65b7b7 100644
--- a/core/src/test/java/org/elasticsearch/index/translog/TranslogTests.java
+++ b/core/src/test/java/org/elasticsearch/index/translog/TranslogTests.java
@@ -34,6 +34,7 @@ import org.elasticsearch.common.io.FileSystemUtils;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.util.BigArrays;
 import org.elasticsearch.common.util.concurrent.AbstractRunnable;
 import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
@@ -276,32 +277,63 @@ public class TranslogTests extends ESTestCase {
         final long firstOperationPosition = translog.getFirstOperationPosition();
         TranslogStats stats = stats();
         assertThat(stats.estimatedNumberOfOperations(), equalTo(0l));
-        long lastSize = stats.translogSizeInBytes().bytes();
+        long lastSize = stats.getTranslogSizeInBytes();
         assertThat((int) firstOperationPosition, greaterThan(CodecUtil.headerLength(TranslogWriter.TRANSLOG_CODEC)));
         assertThat(lastSize, equalTo(firstOperationPosition));
-
+        TranslogStats total = new TranslogStats();
         translog.add(new Translog.Index("test", "1", new byte[]{1}));
         stats = stats();
+        total.add(stats);
         assertThat(stats.estimatedNumberOfOperations(), equalTo(1l));
-        assertThat(stats.translogSizeInBytes().bytes(), greaterThan(lastSize));
-        lastSize = stats.translogSizeInBytes().bytes();
+        assertThat(stats.getTranslogSizeInBytes(), greaterThan(lastSize));
+        lastSize = stats.getTranslogSizeInBytes();
 
         translog.add(new Translog.Delete(newUid("2")));
         stats = stats();
+        total.add(stats);
         assertThat(stats.estimatedNumberOfOperations(), equalTo(2l));
-        assertThat(stats.translogSizeInBytes().bytes(), greaterThan(lastSize));
-        lastSize = stats.translogSizeInBytes().bytes();
+        assertThat(stats.getTranslogSizeInBytes(), greaterThan(lastSize));
+        lastSize = stats.getTranslogSizeInBytes();
 
         translog.add(new Translog.Delete(newUid("3")));
         translog.prepareCommit();
         stats = stats();
+        total.add(stats);
         assertThat(stats.estimatedNumberOfOperations(), equalTo(3l));
-        assertThat(stats.translogSizeInBytes().bytes(), greaterThan(lastSize));
+        assertThat(stats.getTranslogSizeInBytes(), greaterThan(lastSize));
 
         translog.commit();
         stats = stats();
+        total.add(stats);
         assertThat(stats.estimatedNumberOfOperations(), equalTo(0l));
-        assertThat(stats.translogSizeInBytes().bytes(), equalTo(firstOperationPosition));
+        assertThat(stats.getTranslogSizeInBytes(), equalTo(firstOperationPosition));
+        assertEquals(6, total.estimatedNumberOfOperations());
+        assertEquals(431, total.getTranslogSizeInBytes());
+
+        BytesStreamOutput out = new BytesStreamOutput();
+        total.writeTo(out);
+        TranslogStats copy = new TranslogStats();
+        copy.readFrom(StreamInput.wrap(out.bytes()));
+
+        assertEquals(6, copy.estimatedNumberOfOperations());
+        assertEquals(431, copy.getTranslogSizeInBytes());
+        assertEquals("\"translog\"{\n" +
+                "  \"operations\" : 6,\n" +
+                "  \"size_in_bytes\" : 431\n" +
+                "}", copy.toString().trim());
+
+        try {
+            new TranslogStats(1, -1);
+            fail("must be positive");
+        } catch (IllegalArgumentException ex) {
+            //all well
+        }
+        try {
+            new TranslogStats(-1, 1);
+            fail("must be positive");
+        } catch (IllegalArgumentException ex) {
+            //all well
+        }
     }
 
     @Test