diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/DataFileFinder.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/BlockFinder.java
similarity index 59%
rename from skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/DataFileFinder.java
rename to skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/BlockFinder.java
index e84dad1fe..452e0ce9d 100644
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/DataFileFinder.java
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/BlockFinder.java
@@ -1,14 +1,14 @@
-package com.a.eye.skywalking.storage.index;
+package com.a.eye.skywalking.storage.block.index;
 
 /**
  * Created by xin on 2016/11/2.
  */
-public class DataFileFinder {
+public class BlockFinder {
 
-    private IndexL1Cache l1Cache;
-    private IndexL2Cache l2Cache;
+    private L1Cache l1Cache;
+    private L2Cache l2Cache;
 
-    public DataFileFinder(IndexL1Cache l1Cache, IndexL2Cache l2Cache) {
+    public BlockFinder(L1Cache l1Cache, L2Cache l2Cache) {
         this.l1Cache = l1Cache;
         this.l2Cache = l2Cache;
     }
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/BlockIndexEngine.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/BlockIndexEngine.java
new file mode 100644
index 000000000..85b0f9a96
--- /dev/null
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/BlockIndexEngine.java
@@ -0,0 +1,24 @@
+package com.a.eye.skywalking.storage.block.index;
+
+
+public class BlockIndexEngine {
+
+    private static L1Cache l1Cache;
+    private static L2Cache l2Cache;
+
+
+    public static void start(){
+        l1Cache = new L1Cache();
+        l2Cache = new L2Cache();
+        newUpdator().init();
+    }
+
+    public static BlockFinder newFinder() {
+        return new BlockFinder(l1Cache, l2Cache);
+    }
+
+
+    public static BlockIndexUpdator newUpdator() {
+        return new BlockIndexUpdator(l1Cache, l2Cache);
+    }
+}
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/DataFileIndexUpdator.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/BlockIndexUpdator.java
similarity index 75%
rename from skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/DataFileIndexUpdator.java
rename to skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/BlockIndexUpdator.java
index e19a7250d..c71090c89 100644
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/DataFileIndexUpdator.java
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/BlockIndexUpdator.java
@@ -1,6 +1,6 @@
-package com.a.eye.skywalking.storage.index;
+package com.a.eye.skywalking.storage.block.index;
 
-import com.a.eye.skywalking.storage.index.exception.DataFileIndexSaveFailedException;
+import com.a.eye.skywalking.storage.block.index.exception.BlockIndexPersistenceFailedException;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -12,13 +12,13 @@ import java.util.List;
 import static com.a.eye.skywalking.storage.config.Config.DataFileIndex.DATA_FILE_INDEX_FILE_NAME;
 import static com.a.eye.skywalking.storage.config.Config.DataFileIndex.STORAGE_BASE_PATH;
 
-public class DataFileIndexUpdator {
+public class BlockIndexUpdator {
 
-    private static Logger logger = LogManager.getLogger(DataFileIndexUpdator.class);
-    private IndexL1Cache l1Cache;
-    private IndexL2Cache l2Cache;
+    private static Logger logger = LogManager.getLogger(BlockIndexUpdator.class);
+    private L1Cache l1Cache;
+    private L2Cache l2Cache;
 
-    public DataFileIndexUpdator(IndexL1Cache l1Cache, IndexL2Cache l2Cache) {
+    public BlockIndexUpdator(L1Cache l1Cache, L2Cache l2Cache) {
         this.l1Cache = l1Cache;
         this.l2Cache = l2Cache;
     }
@@ -34,12 +34,12 @@ public class DataFileIndexUpdator {
     }
 
     private void updateCache(long timestamp) {
-        l1Cache.update(timestamp);
-        l2Cache.update(timestamp);
+        l1Cache.add2Rebuild(timestamp);
+        l2Cache.add2Rebuild(timestamp);
     }
 
 
-    private void updateFile(long timestamp) throws DataFileIndexSaveFailedException {
+    private void updateFile(long timestamp) throws BlockIndexPersistenceFailedException {
         BufferedWriter writer = null;
         try {
             writer = new BufferedWriter(new FileWriter(new File(STORAGE_BASE_PATH, DATA_FILE_INDEX_FILE_NAME)));
@@ -47,7 +47,7 @@ public class DataFileIndexUpdator {
             writer.newLine();
             writer.close();
         } catch (IOException e) {
-            throw new DataFileIndexSaveFailedException("Failed to save index[" + timestamp + "]", e);
+            throw new BlockIndexPersistenceFailedException("Failed to save index[" + timestamp + "]", e);
         } finally {
             if (writer != null) {
                 try {
@@ -83,7 +83,7 @@ public class DataFileIndexUpdator {
         }
 
         Collections.reverse(indexData);
-        l1Cache.initData(indexData);
-        l2Cache.initData(indexData);
+        l1Cache.init(indexData);
+        l2Cache.init(indexData);
     }
 }
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/IndexL1Cache.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/L1Cache.java
similarity index 87%
rename from skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/IndexL1Cache.java
rename to skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/L1Cache.java
index b50042979..f8f9a3e65 100644
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/IndexL1Cache.java
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/L1Cache.java
@@ -1,4 +1,4 @@
-package com.a.eye.skywalking.storage.index;
+package com.a.eye.skywalking.storage.block.index;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -10,16 +10,18 @@ import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 /**
+ * 块索引的一级缓存
+ *
  * Created by xin on 2016/11/2.
  */
-public class IndexL1Cache {
+public class L1Cache {
 
     private static final int           MAX_DATA_KEEP_SIZE = 30;
-    private static       Logger        logger             = LogManager.getLogger(IndexL1Cache.class);
+    private static       Logger        logger             = LogManager.getLogger(L1Cache.class);
     private              TreeSet<Long> cacheData          = new TreeSet<Long>();
     private final        ReadWriteLock updateLock         = new ReentrantReadWriteLock();
 
-    void initData(List<Long> data) {
+    void init(List<Long> data) {
         for (int i = 0; i < MAX_DATA_KEEP_SIZE; i++) {
             this.cacheData.add(data.get(i));
         }
@@ -35,7 +37,7 @@ public class IndexL1Cache {
         }
     }
 
-    public void update(long timestamp) {
+    public void add2Rebuild(long timestamp) {
         TreeSet<Long> newCacheData = new TreeSet<>(cacheData);
         newCacheData.add(timestamp);
 
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/IndexL2Cache.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/L2Cache.java
similarity index 82%
rename from skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/IndexL2Cache.java
rename to skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/L2Cache.java
index 5f59cb0f5..f1ed5ad01 100644
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/IndexL2Cache.java
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/L2Cache.java
@@ -1,4 +1,4 @@
-package com.a.eye.skywalking.storage.index;
+package com.a.eye.skywalking.storage.block.index;
 
 import java.util.List;
 import java.util.TreeSet;
@@ -6,12 +6,15 @@ import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
-public class IndexL2Cache {
+/**
+ * 块索引的二级缓存
+ */
+public class L2Cache {
 
     private TreeSet<Long> cacheData  = new TreeSet<Long>();
     private ReadWriteLock updateLock = new ReentrantReadWriteLock();
 
-    void initData(List<Long> data) {
+    void init(List<Long> data) {
         this.cacheData.addAll(cacheData);
     }
 
@@ -25,7 +28,7 @@ public class IndexL2Cache {
         }
     }
 
-    public void update(long timestamp) {
+    public void add2Rebuild(long timestamp) {
         TreeSet<Long> newCacheData = new TreeSet<>(cacheData);
         newCacheData.add(timestamp);
         Lock lock = updateLock.writeLock();
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/exception/BlockIndexPersistenceFailedException.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/exception/BlockIndexPersistenceFailedException.java
new file mode 100644
index 000000000..03b2ef169
--- /dev/null
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/block/index/exception/BlockIndexPersistenceFailedException.java
@@ -0,0 +1,10 @@
+package com.a.eye.skywalking.storage.block.index.exception;
+
+/**
+ * Created by xin on 2016/11/2.
+ */
+public class BlockIndexPersistenceFailedException extends Exception {
+    public BlockIndexPersistenceFailedException(String message, Exception e) {
+        super(message, e);
+    }
+}
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/DataFileIndexEngine.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/DataFileIndexEngine.java
deleted file mode 100644
index 7591cc95d..000000000
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/DataFileIndexEngine.java
+++ /dev/null
@@ -1,24 +0,0 @@
-package com.a.eye.skywalking.storage.index;
-
-
-public class DataFileIndexEngine {
-
-    private static IndexL1Cache l1Cache;
-    private static IndexL2Cache l2Cache;
-
-
-    public static void start(){
-        l1Cache = new IndexL1Cache();
-        l2Cache = new IndexL2Cache();
-        newUpdator().init();
-    }
-
-    public static DataFileFinder newFinder() {
-        return new DataFileFinder(l1Cache, l2Cache);
-    }
-
-
-    public static DataFileIndexUpdator newUpdator() {
-        return new DataFileIndexUpdator(l1Cache, l2Cache);
-    }
-}
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/exception/DataFileIndexSaveFailedException.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/exception/DataFileIndexSaveFailedException.java
deleted file mode 100644
index 8cfa047f2..000000000
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/index/exception/DataFileIndexSaveFailedException.java
+++ /dev/null
@@ -1,10 +0,0 @@
-package com.a.eye.skywalking.storage.index.exception;
-
-/**
- * Created by xin on 2016/11/2.
- */
-public class DataFileIndexSaveFailedException extends Exception {
-    public DataFileIndexSaveFailedException(String message, Exception e) {
-        super(message, e);
-    }
-}
diff --git a/skywalking-storage-center/skywalking-storage/src/test/java/com/a/eye/skywalking/storage/index/DataIndexFileOperator.java b/skywalking-storage-center/skywalking-storage/src/test/java/com/a/eye/skywalking/storage/block/index/DataIndexFileOperator.java
similarity index 61%
rename from skywalking-storage-center/skywalking-storage/src/test/java/com/a/eye/skywalking/storage/index/DataIndexFileOperator.java
rename to skywalking-storage-center/skywalking-storage/src/test/java/com/a/eye/skywalking/storage/block/index/DataIndexFileOperator.java
index 770b2113b..66024e856 100644
--- a/skywalking-storage-center/skywalking-storage/src/test/java/com/a/eye/skywalking/storage/index/DataIndexFileOperator.java
+++ b/skywalking-storage-center/skywalking-storage/src/test/java/com/a/eye/skywalking/storage/block/index/DataIndexFileOperator.java
@@ -1,4 +1,4 @@
-package com.a.eye.skywalking.storage.index;
+package com.a.eye.skywalking.storage.block.index;
 
 /**
  * Created by xin on 2016/10/31.