diff --git a/weed/storage/volume.go b/weed/storage/volume.go
index 801dfe267..258787701 100644
--- a/weed/storage/volume.go
+++ b/weed/storage/volume.go
@@ -10,6 +10,11 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/glog"
 )
 
+type keyField struct {
+	offset uint32
+	size   uint32
+}
+
 type Volume struct {
 	Id            VolumeId
 	dir           string
@@ -23,6 +28,9 @@ type Volume struct {
 
 	dataFileAccessLock sync.Mutex
 	lastModifiedTime   uint64 //unix time in seconds
+
+	lastCompactingIndexOffset       uint64
+	incrementedHasUpdatedIndexEntry map[uint64]keyField
 }
 
 func NewVolume(dirname string, collection string, id VolumeId, needleMapKind NeedleMapType, replicaPlacement *ReplicaPlacement, ttl *TTL) (v *Volume, e error) {
diff --git a/weed/storage/volume_vacuum.go b/weed/storage/volume_vacuum.go
index 51d74e311..55c248894 100644
--- a/weed/storage/volume_vacuum.go
+++ b/weed/storage/volume_vacuum.go
@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/util"
 )
 
 func (v *Volume) garbageLevel() float64 {
@@ -20,7 +21,8 @@ func (v *Volume) Compact() error {
 	//glog.V(3).Infof("Got Compaction lock...")
 
 	filePath := v.FileName()
-	glog.V(3).Infof("creating copies for volume %d ...", v.Id)
+	v.lastCompactingIndexOffset = v.nm.IndexFileSize()
+	glog.V(3).Infof("creating copies for volume %d ,last offset %d...", v.Id, v.lastCompactingIndexOffset)
 	return v.copyDataAndGenerateIndexFile(filePath+".cpd", filePath+".cpx")
 }
 
@@ -38,14 +40,28 @@ func (v *Volume) commitCompact() error {
 	glog.V(3).Infof("Got Committing lock...")
 	v.nm.Close()
 	_ = v.dataFile.Close()
-	makeupDiff(v.FileName()+".cpd", v.FileName()+".cpx", v.FileName()+".dat", v.FileName()+".idx")
+
 	var e error
-	if e = os.Rename(v.FileName()+".cpd", v.FileName()+".dat"); e != nil {
-		return e
-	}
-	if e = os.Rename(v.FileName()+".cpx", v.FileName()+".idx"); e != nil {
-		return e
+	if e = v.makeupDiff(v.FileName()+".cpd", v.FileName()+".cpx", v.FileName()+".dat", v.FileName()+".idx"); e != nil {
+		glog.V(0).Infof("makeupDiff in commitCompact failed %v", e)
+		e = os.Remove(v.FileName() + ".cpd")
+		if e != nil {
+			return e
+		}
+		e = os.Remove(v.FileName() + ".cpx")
+		if e != nil {
+			return e
+		}
+	} else {
+		var e error
+		if e = os.Rename(v.FileName()+".cpd", v.FileName()+".dat"); e != nil {
+			return e
+		}
+		if e = os.Rename(v.FileName()+".cpx", v.FileName()+".idx"); e != nil {
+			return e
+		}
 	}
+
 	//glog.V(3).Infof("Pretending to be vacuuming...")
 	//time.Sleep(20 * time.Second)
 	glog.V(3).Infof("Loading Commit file...")
@@ -55,7 +71,85 @@ func (v *Volume) commitCompact() error {
 	return nil
 }
 
-func makeupDiff(newDatFile, newIdxFile, oldDatFile, oldIdxFile string) (err error) {
+func (v *Volume) makeupDiff(newDatFileName, newIdxFileName, oldDatFileName, oldIdxFileName string) (err error) {
+	var indexSize int64
+
+	oldIdxFile, err := os.Open(oldIdxFileName)
+	defer oldIdxFile.Close()
+
+	oldDatFile, err := os.Open(oldDatFileName)
+	defer oldDatFile.Close()
+
+	if indexSize, err = verifyIndexFileIntegrity(oldIdxFile); err != nil {
+		return fmt.Errorf("verifyIndexFileIntegrity %s failed: %v", oldIdxFileName, err)
+	}
+	if indexSize == 0 || uint64(indexSize) <= v.lastCompactingIndexOffset {
+		return nil
+	}
+
+	v.incrementedHasUpdatedIndexEntry = make(map[uint64]keyField)
+	for idx_offset := indexSize; uint64(idx_offset) >= v.lastCompactingIndexOffset; idx_offset -= NeedleIndexSize {
+		var IdxEntry []byte
+		if IdxEntry, err = readIndexEntryAtOffset(oldIdxFile, idx_offset); err != nil {
+			return fmt.Errorf("readIndexEntry %s at offset %d failed: %v", oldIdxFileName, idx_offset, err)
+		}
+		key, offset, size := idxFileEntry(IdxEntry)
+		if _, found := v.incrementedHasUpdatedIndexEntry[key]; !found {
+			v.incrementedHasUpdatedIndexEntry[key] = keyField{
+				offset: offset,
+				size:   size,
+			}
+		} else {
+			continue
+		}
+	}
+
+	if len(v.incrementedHasUpdatedIndexEntry) > 0 {
+		var (
+			dst, idx *os.File
+		)
+		if dst, err = os.OpenFile(newDatFileName, os.O_WRONLY, 0644); err != nil {
+			return
+		}
+		defer dst.Close()
+
+		if idx, err = os.OpenFile(newIdxFileName, os.O_WRONLY, 0644); err != nil {
+			return
+		}
+		defer idx.Close()
+
+		idx_entry_bytes := make([]byte, 16)
+		for key, incre_idx_entry := range v.incrementedHasUpdatedIndexEntry {
+			util.Uint64toBytes(idx_entry_bytes[0:8], key)
+			util.Uint32toBytes(idx_entry_bytes[8:12], incre_idx_entry.offset)
+			util.Uint32toBytes(idx_entry_bytes[12:16], incre_idx_entry.size)
+
+			if _, err := idx.Seek(0, 2); err != nil {
+				return fmt.Errorf("cannot seek end of indexfile %s: %v",
+					newIdxFileName, err)
+			}
+			_, err = idx.Write(idx_entry_bytes)
+
+			//even the needle cache in memory is hit, the need_bytes is correct
+			needle_bytes, _, _ := ReadNeedleBlob(dst, int64(incre_idx_entry.offset)*NeedlePaddingSize, incre_idx_entry.size)
+
+			var offset int64
+			if offset, err = dst.Seek(0, 2); err != nil {
+				glog.V(0).Infof("failed to seek the end of file: %v", err)
+				return
+			}
+			//ensure file writing starting from aligned positions
+			if offset%NeedlePaddingSize != 0 {
+				offset = offset + (NeedlePaddingSize - offset%NeedlePaddingSize)
+				if offset, err = v.dataFile.Seek(offset, 0); err != nil {
+					glog.V(0).Infof("failed to align in datafile %s: %v", v.dataFile.Name(), err)
+					return
+				}
+			}
+			dst.Write(needle_bytes)
+		}
+	}
+
 	return nil
 }