diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/DefaultMobCompactor.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/DefaultMobCompactor.java
index d0c81759410..47dd0b18e71 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/DefaultMobCompactor.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/DefaultMobCompactor.java
@@ -219,7 +219,8 @@ public class DefaultMobCompactor extends DefaultCompactor {
       } while (hasMore);
     } finally {
       if (mobFileWriter != null) {
-        appendMetadataAndCloseWriter(mobFileWriter, fd, major);
+        mobFileWriter.appendMetadata(fd.maxSeqId, major, mobCells);
+        mobFileWriter.close();
       }
     }
     if(mobFileWriter!=null) {
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/DefaultMobStoreFlusher.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/DefaultMobStoreFlusher.java
index 194e8988cd3..00b3421b057 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/DefaultMobStoreFlusher.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/DefaultMobStoreFlusher.java
@@ -196,7 +196,7 @@ public class DefaultMobStoreFlusher extends DefaultStoreFlusher {
       } while (hasMore);
     } finally {
       status.setStatus("Flushing mob file " + store + ": appending metadata");
-      mobFileWriter.appendMetadata(cacheFlushId, false);
+      mobFileWriter.appendMetadata(cacheFlushId, false, mobCount);
       status.setStatus("Flushing mob file " + store + ": closing flushed file");
       mobFileWriter.close();
     }
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/mapreduce/MemStoreWrapper.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/mapreduce/MemStoreWrapper.java
index b0d4c9d8f23..d286b7259ff 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/mapreduce/MemStoreWrapper.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/mob/mapreduce/MemStoreWrapper.java
@@ -122,7 +122,7 @@ public class MemStoreWrapper {
    */
   private void internalFlushCache(final MemStoreSnapshot snapshot)
       throws IOException {
-    if (snapshot.getSize() == 0) {
+    if (snapshot.getCellsCount() == 0) {
       return;
     }
     // generate the files into a temp directory.
@@ -135,18 +135,16 @@ public class MemStoreWrapper {
     LOG.info("Create files under a temp directory " + mobFileWriter.getPath().toString());
 
     byte[] referenceValue = Bytes.toBytes(relativePath);
-    int keyValueCount = 0;
     KeyValueScanner scanner = snapshot.getScanner();
     Cell cell = null;
     while (null != (cell = scanner.next())) {
       KeyValue kv = KeyValueUtil.ensureKeyValue(cell);
       mobFileWriter.append(kv);
-      keyValueCount++;
     }
     scanner.close();
     // Write out the log sequence number that corresponds to this output
     // hfile. The hfile is current up to and including logCacheFlushId.
-    mobFileWriter.appendMetadata(Long.MAX_VALUE, false);
+    mobFileWriter.appendMetadata(Long.MAX_VALUE, false, snapshot.getCellsCount());
     mobFileWriter.close();
 
     MobUtils.commitFile(conf, fs, mobFileWriter.getPath(), mobFamilyDir, cacheConfig);
@@ -164,9 +162,7 @@ public class MemStoreWrapper {
       table.put(put);
       context.getCounter(SweepCounter.RECORDS_UPDATED).increment(1);
     }
-    if (keyValueCount > 0) {
-      table.flushCommits();
-    }
+    table.flushCommits();
     scanner.close();
   }
 
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreFile.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreFile.java
index 13ded588be4..56ae51a169d 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreFile.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreFile.java
@@ -112,6 +112,9 @@ public class StoreFile {
   /** Key for timestamp of earliest-put in metadata*/
   public static final byte[] EARLIEST_PUT_TS = Bytes.toBytes("EARLIEST_PUT_TS");
 
+  /** Key for the number of mob cells in metadata*/
+  public static final byte[] MOB_CELLS_COUNT = Bytes.toBytes("MOB_CELLS_COUNT");
+
   private final StoreFileInfo fileInfo;
   private final FileSystem fs;
 
@@ -779,6 +782,22 @@ public class StoreFile {
       appendTrackedTimestampsToMetadata();
     }
 
+    /**
+     * Writes meta data.
+     * Call before {@link #close()} since its written as meta data to this file.
+     * @param maxSequenceId Maximum sequence id.
+     * @param majorCompaction True if this file is product of a major compaction
+     * @param mobCellsCount The number of mob cells.
+     * @throws IOException problem writing to FS
+     */
+    public void appendMetadata(final long maxSequenceId, final boolean majorCompaction,
+        final long mobCellsCount) throws IOException {
+      writer.appendFileInfo(MAX_SEQ_ID_KEY, Bytes.toBytes(maxSequenceId));
+      writer.appendFileInfo(MAJOR_COMPACTION_KEY, Bytes.toBytes(majorCompaction));
+      writer.appendFileInfo(MOB_CELLS_COUNT, Bytes.toBytes(mobCellsCount));
+      appendTrackedTimestampsToMetadata();
+    }
+
     /**
      * Add TimestampRange and earliest put timestamp to Metadata
      */
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestMobCompaction.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestMobCompaction.java
index f44e5299e00..3234628eb5f 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestMobCompaction.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestMobCompaction.java
@@ -27,6 +27,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Random;
 import java.util.Set;
 
@@ -169,6 +170,8 @@ public class TestMobCompaction {
     assertEquals("Before compaction: mob file count", compactionThreshold, countMobFiles());
     assertEquals("Before compaction: rows", compactionThreshold, countRows());
     assertEquals("Before compaction: mob rows", compactionThreshold, countMobRows());
+    assertEquals("Before compaction: number of mob cells", compactionThreshold,
+        countMobCellsInMetadata());
     // Change the threshold larger than the data size
     region.getTableDesc().getFamily(COLUMN_FAMILY).setMobThreshold(500);
     region.initialize();
@@ -217,6 +220,8 @@ public class TestMobCompaction {
     assertEquals("After compaction: rows", compactionThreshold, countRows());
     assertEquals("After compaction: mob rows", compactionThreshold, countMobRows());
     assertEquals("After compaction: referenced mob file count", 1, countReferencedMobFiles());
+    assertEquals("After compaction: number of mob cells", compactionThreshold,
+        countMobCellsInMetadata());
   }
 
   /**
@@ -290,6 +295,26 @@ public class TestMobCompaction {
     return 0;
   }
 
+  private long countMobCellsInMetadata() throws IOException {
+    long mobCellsCount = 0;
+    Path mobDirPath = new Path(MobUtils.getMobRegionPath(conf, htd.getTableName()),
+        hcd.getNameAsString());
+    Configuration copyOfConf = new Configuration(conf);
+    copyOfConf.setFloat(HConstants.HFILE_BLOCK_CACHE_SIZE_KEY, 0f);
+    CacheConfig cacheConfig = new CacheConfig(copyOfConf);
+    if (fs.exists(mobDirPath)) {
+      FileStatus[] files = UTIL.getTestFileSystem().listStatus(mobDirPath);
+      for (FileStatus file : files) {
+        StoreFile sf = new StoreFile(fs, file.getPath(), conf, cacheConfig, BloomType.NONE);
+        Map<byte[], byte[]> fileInfo = sf.createReader().loadFileInfo();
+        byte[] count = fileInfo.get(StoreFile.MOB_CELLS_COUNT);
+        assertTrue(count != null);
+        mobCellsCount += Bytes.toLong(count);
+      }
+    }
+    return mobCellsCount;
+  }
+
   private Put createPut(int rowIdx, byte[] dummyData) throws IOException {
     Put p = new Put(Bytes.add(STARTROW, Bytes.toBytes(rowIdx)));
     p.setDurability(Durability.SKIP_WAL);