diff --git a/unmaintained/fix_dat/fix_dat.go b/unmaintained/fix_dat/fix_dat.go
index bcb985fe9..1f95e6cd6 100644
--- a/unmaintained/fix_dat/fix_dat.go
+++ b/unmaintained/fix_dat/fix_dat.go
@@ -60,7 +60,7 @@ func main() {
 
 	iterateEntries(datFile, indexFile, func(n *storage.Needle, offset int64) {
 		fmt.Printf("file id=%d name=%s size=%d dataSize=%d\n", n.Id, string(n.Name), n.Size, n.DataSize)
-		s, e := n.Append(newDatFile, storage.Version2)
+		s, _, e := n.Append(newDatFile, storage.Version2)
 		fmt.Printf("size %d error %v\n", s, e)
 	})
 
diff --git a/weed/command/fix.go b/weed/command/fix.go
index 2ec74d026..22480dcd0 100644
--- a/weed/command/fix.go
+++ b/weed/command/fix.go
@@ -58,7 +58,7 @@ func runFix(cmd *Command, args []string) bool {
 				glog.V(2).Infof("saved %d with error %v", n.Size, pe)
 			} else {
 				glog.V(2).Infof("skipping deleted file ...")
-				return nm.Delete(n.Id)
+				return nm.Delete(n.Id, uint32(offset/storage.NeedlePaddingSize))
 			}
 			return nil
 		})
diff --git a/weed/storage/disk_location.go b/weed/storage/disk_location.go
index e7604a734..039b4f3b9 100644
--- a/weed/storage/disk_location.go
+++ b/weed/storage/disk_location.go
@@ -40,7 +40,12 @@ func (l *DiskLocation) loadExistingVolume(dir os.FileInfo, needleMapKind NeedleM
 					mutex.Lock()
 					l.volumes[vid] = v
 					mutex.Unlock()
-					glog.V(0).Infof("data file %s, replicaPlacement=%s v=%d size=%d ttl=%s", l.Directory+"/"+name, v.ReplicaPlacement, v.Version(), v.Size(), v.Ttl.String())
+					glog.V(0).Infof("data file %s, replicaPlacement=%s v=%d size=%d ttl=%s",
+						l.Directory+"/"+name, v.ReplicaPlacement, v.Version(), v.Size(), v.Ttl.String())
+					if v.Size() != v.dataFileSize {
+						glog.V(0).Infof("data file %s, size=%d expected=%d",
+							l.Directory+"/"+name, v.Size(), v.dataFileSize)
+					}
 				} else {
 					glog.V(0).Infof("new volume %s error %s", name, e)
 				}
diff --git a/weed/storage/needle.go b/weed/storage/needle.go
index daa050be8..1d306395e 100644
--- a/weed/storage/needle.go
+++ b/weed/storage/needle.go
@@ -3,6 +3,7 @@ package storage
 import (
 	"fmt"
 	"io/ioutil"
+	"math"
 	"mime"
 	"net/http"
 	"path"
@@ -20,6 +21,7 @@ const (
 	NeedlePaddingSize     = 8
 	NeedleChecksumSize    = 4
 	MaxPossibleVolumeSize = 4 * 1024 * 1024 * 1024 * 8
+	TombstoneFileSize     = math.MaxUint32
 )
 
 /*
diff --git a/weed/storage/needle_map.go b/weed/storage/needle_map.go
index 142018946..15a0387c5 100644
--- a/weed/storage/needle_map.go
+++ b/weed/storage/needle_map.go
@@ -24,7 +24,7 @@ const (
 type NeedleMapper interface {
 	Put(key uint64, offset uint32, size uint32) error
 	Get(key uint64) (element *NeedleValue, ok bool)
-	Delete(key uint64) error
+	Delete(key uint64, offset uint32) error
 	Close()
 	Destroy() error
 	ContentSize() uint64
diff --git a/weed/storage/needle_map_boltdb.go b/weed/storage/needle_map_boltdb.go
index bd3edf28d..e131ea822 100644
--- a/weed/storage/needle_map_boltdb.go
+++ b/weed/storage/needle_map_boltdb.go
@@ -63,7 +63,7 @@ func generateBoltDbFile(dbFileName string, indexFile *os.File) error {
 	}
 	defer db.Close()
 	return WalkIndexFile(indexFile, func(key uint64, offset, size uint32) error {
-		if offset > 0 {
+		if offset > 0 && size != TombstoneFileSize {
 			boltDbWrite(db, key, offset, size)
 		} else {
 			boltDbDelete(db, key)
@@ -143,12 +143,12 @@ func boltDbDelete(db *bolt.DB, key uint64) error {
 	})
 }
 
-func (m *BoltDbNeedleMap) Delete(key uint64) error {
+func (m *BoltDbNeedleMap) Delete(key uint64, offset uint32) error {
 	if oldNeedle, ok := m.Get(key); ok {
 		m.logDelete(oldNeedle.Size)
 	}
 	// write to index file first
-	if err := m.appendToIndexFile(key, 0, 0); err != nil {
+	if err := m.appendToIndexFile(key, offset, TombstoneFileSize); err != nil {
 		return err
 	}
 	return boltDbDelete(m.db, key)
diff --git a/weed/storage/needle_map_leveldb.go b/weed/storage/needle_map_leveldb.go
index 1789dbb12..f025ea360 100644
--- a/weed/storage/needle_map_leveldb.go
+++ b/weed/storage/needle_map_leveldb.go
@@ -61,7 +61,7 @@ func generateLevelDbFile(dbFileName string, indexFile *os.File) error {
 	}
 	defer db.Close()
 	return WalkIndexFile(indexFile, func(key uint64, offset, size uint32) error {
-		if offset > 0 {
+		if offset > 0 && size != TombstoneFileSize {
 			levelDbWrite(db, key, offset, size)
 		} else {
 			levelDbDelete(db, key)
@@ -112,12 +112,12 @@ func levelDbDelete(db *leveldb.DB, key uint64) error {
 	return db.Delete(bytes, nil)
 }
 
-func (m *LevelDbNeedleMap) Delete(key uint64) error {
+func (m *LevelDbNeedleMap) Delete(key uint64, offset uint32) error {
 	if oldNeedle, ok := m.Get(key); ok {
 		m.logDelete(oldNeedle.Size)
 	}
 	// write to index file first
-	if err := m.appendToIndexFile(key, 0, 0); err != nil {
+	if err := m.appendToIndexFile(key, offset, TombstoneFileSize); err != nil {
 		return err
 	}
 	return levelDbDelete(m.db, key)
diff --git a/weed/storage/needle_map_memory.go b/weed/storage/needle_map_memory.go
index 195d8bdbc..6fa929d90 100644
--- a/weed/storage/needle_map_memory.go
+++ b/weed/storage/needle_map_memory.go
@@ -33,7 +33,7 @@ func LoadNeedleMap(file *os.File) (*NeedleMap, error) {
 		}
 		nm.FileCounter++
 		nm.FileByteCounter = nm.FileByteCounter + uint64(size)
-		if offset > 0 {
+		if offset > 0 && size != TombstoneFileSize {
 			oldSize := nm.m.Set(Key(key), offset, size)
 			glog.V(3).Infoln("reading key", key, "offset", offset*NeedlePaddingSize, "size", size, "oldSize", oldSize)
 			if oldSize > 0 {
@@ -92,10 +92,10 @@ func (nm *NeedleMap) Get(key uint64) (element *NeedleValue, ok bool) {
 	element, ok = nm.m.Get(Key(key))
 	return
 }
-func (nm *NeedleMap) Delete(key uint64) error {
+func (nm *NeedleMap) Delete(key uint64, offset uint32) error {
 	deletedBytes := nm.m.Delete(Key(key))
 	nm.logDelete(deletedBytes)
-	return nm.appendToIndexFile(key, 0, 0)
+	return nm.appendToIndexFile(key, offset, TombstoneFileSize)
 }
 func (nm *NeedleMap) Close() {
 	_ = nm.indexFile.Close()
diff --git a/weed/storage/needle_read_write.go b/weed/storage/needle_read_write.go
index 3ac236951..8baa325df 100644
--- a/weed/storage/needle_read_write.go
+++ b/weed/storage/needle_read_write.go
@@ -22,10 +22,10 @@ const (
 )
 
 func (n *Needle) DiskSize() int64 {
-	padding := NeedlePaddingSize - ((NeedleHeaderSize + int64(n.Size) + NeedleChecksumSize) % NeedlePaddingSize)
-	return NeedleHeaderSize + int64(n.Size) + padding + NeedleChecksumSize
+	return getActualSize(n.Size)
 }
-func (n *Needle) Append(w io.Writer, version Version) (size uint32, err error) {
+
+func (n *Needle) Append(w io.Writer, version Version) (size uint32, actualSize int64, err error) {
 	if s, ok := w.(io.Seeker); ok {
 		if end, e := s.Seek(0, 1); e == nil {
 			defer func(s io.Seeker, off int64) {
@@ -54,6 +54,7 @@ func (n *Needle) Append(w io.Writer, version Version) (size uint32, err error) {
 		if _, err = w.Write(n.Data); err != nil {
 			return
 		}
+		actualSize = NeedleHeaderSize + int64(n.Size)
 		padding := NeedlePaddingSize - ((NeedleHeaderSize + n.Size + NeedleChecksumSize) % NeedlePaddingSize)
 		util.Uint32toBytes(header[0:NeedleChecksumSize], n.Checksum.Value())
 		_, err = w.Write(header[0 : NeedleChecksumSize+padding])
@@ -131,9 +132,12 @@ func (n *Needle) Append(w io.Writer, version Version) (size uint32, err error) {
 		padding := NeedlePaddingSize - ((NeedleHeaderSize + n.Size + NeedleChecksumSize) % NeedlePaddingSize)
 		util.Uint32toBytes(header[0:NeedleChecksumSize], n.Checksum.Value())
 		_, err = w.Write(header[0 : NeedleChecksumSize+padding])
-		return n.DataSize, err
+
+		actualSize = NeedleHeaderSize + int64(n.Size) + NeedleChecksumSize + int64(padding)
+
+		return n.DataSize, actualSize, err
 	}
-	return 0, fmt.Errorf("Unsupported Version! (%d)", version)
+	return 0, 0, fmt.Errorf("Unsupported Version! (%d)", version)
 }
 
 func ReadNeedleBlob(r *os.File, offset int64, size uint32) (dataSlice []byte, block *Block, err error) {
diff --git a/weed/storage/volume.go b/weed/storage/volume.go
index dfd623eaa..11ee600df 100644
--- a/weed/storage/volume.go
+++ b/weed/storage/volume.go
@@ -15,6 +15,7 @@ type Volume struct {
 	dir           string
 	Collection    string
 	dataFile      *os.File
+	dataFileSize  int64
 	nm            NeedleMapper
 	needleMapKind NeedleMapType
 	readOnly      bool
diff --git a/weed/storage/volume_checking.go b/weed/storage/volume_checking.go
index 48f707594..6d4011f27 100644
--- a/weed/storage/volume_checking.go
+++ b/weed/storage/volume_checking.go
@@ -7,27 +7,33 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/util"
 )
 
-func CheckVolumeDataIntegrity(v *Volume, indexFile *os.File) error {
+func getActualSize(size uint32) int64 {
+	padding := NeedlePaddingSize - ((NeedleHeaderSize + size + NeedleChecksumSize) % NeedlePaddingSize)
+	return NeedleHeaderSize + int64(size) + NeedleChecksumSize + int64(padding)
+}
+
+func CheckVolumeDataIntegrity(v *Volume, indexFile *os.File) (int64, error) {
 	var indexSize int64
 	var e error
 	if indexSize, e = verifyIndexFileIntegrity(indexFile); e != nil {
-		return fmt.Errorf("verifyIndexFileIntegrity %s failed: %v", indexFile.Name(), e)
+		return 0, fmt.Errorf("verifyIndexFileIntegrity %s failed: %v", indexFile.Name(), e)
 	}
 	if indexSize == 0 {
-		return nil
+		return int64(SuperBlockSize), nil
 	}
 	var lastIdxEntry []byte
 	if lastIdxEntry, e = readIndexEntryAtOffset(indexFile, indexSize-NeedleIndexSize); e != nil {
-		return fmt.Errorf("readLastIndexEntry %s failed: %v", indexFile.Name(), e)
+		return 0, fmt.Errorf("readLastIndexEntry %s failed: %v", indexFile.Name(), e)
 	}
 	key, offset, size := idxFileEntry(lastIdxEntry)
-	if offset == 0 {
-		return nil
+	if offset == 0 || size == TombstoneFileSize {
+		return 0, nil
 	}
 	if e = verifyNeedleIntegrity(v.dataFile, v.Version(), int64(offset)*NeedlePaddingSize, key, size); e != nil {
-		return fmt.Errorf("verifyNeedleIntegrity %s failed: %v", indexFile.Name(), e)
+		return 0, fmt.Errorf("verifyNeedleIntegrity %s failed: %v", indexFile.Name(), e)
 	}
-	return nil
+
+	return int64(offset)*int64(NeedlePaddingSize) + getActualSize(size), nil
 }
 
 func verifyIndexFileIntegrity(indexFile *os.File) (indexSize int64, err error) {
diff --git a/weed/storage/volume_loading.go b/weed/storage/volume_loading.go
index f2099de83..7bc65a4a3 100644
--- a/weed/storage/volume_loading.go
+++ b/weed/storage/volume_loading.go
@@ -64,7 +64,7 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 				return fmt.Errorf("cannot write Volume Index %s.idx: %v", fileName, e)
 			}
 		}
-		if e = CheckVolumeDataIntegrity(v, indexFile); e != nil {
+		if v.dataFileSize, e = CheckVolumeDataIntegrity(v, indexFile); e != nil {
 			v.readOnly = true
 			glog.V(0).Infof("volumeDataIntegrityChecking failed %v", e)
 		}
@@ -86,6 +86,7 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 			}
 		}
 	}
+
 	return e
 }
 
diff --git a/weed/storage/volume_read_write.go b/weed/storage/volume_read_write.go
index 7458b4879..66f18557f 100644
--- a/weed/storage/volume_read_write.go
+++ b/weed/storage/volume_read_write.go
@@ -60,6 +60,8 @@ func (v *Volume) AppendBlob(b []byte) (offset int64, err error) {
 	if offset, err = v.dataFile.Seek(0, 2); err != nil {
 		glog.V(0).Infof("failed to seek the end of file: %v", err)
 		return
+	} else if offset != int64(v.dataFileSize) {
+		glog.V(0).Infof("dataFileSize %d != actual data file size: %d", v.dataFileSize, offset)
 	}
 	//ensure file writing starting from aligned positions
 	if offset%NeedlePaddingSize != 0 {
@@ -67,9 +69,12 @@ func (v *Volume) AppendBlob(b []byte) (offset int64, err error) {
 		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
+		} else if offset != int64(v.dataFileSize) {
+			glog.V(0).Infof("dataFileSize %d != actual data file size: %d", v.dataFileSize, offset)
 		}
 	}
-	v.dataFile.Write(b)
+	_, err = v.dataFile.Write(b)
+	v.dataFileSize += int64(len(b))
 	return
 }
 
@@ -86,10 +91,12 @@ func (v *Volume) writeNeedle(n *Needle) (size uint32, err error) {
 		glog.V(4).Infof("needle is unchanged!")
 		return
 	}
-	var offset int64
+	var offset, actualSize int64
 	if offset, err = v.dataFile.Seek(0, 2); err != nil {
 		glog.V(0).Infof("failed to seek the end of file: %v", err)
 		return
+	} else if offset != int64(v.dataFileSize) {
+		glog.V(0).Infof("dataFileSize %d != actual data file size: %d", v.dataFileSize, offset)
 	}
 
 	//ensure file writing starting from aligned positions
@@ -101,12 +108,14 @@ func (v *Volume) writeNeedle(n *Needle) (size uint32, err error) {
 		}
 	}
 
-	if size, err = n.Append(v.dataFile, v.Version()); err != nil {
+	if size, actualSize, err = n.Append(v.dataFile, v.Version()); err != nil {
 		if e := v.dataFile.Truncate(offset); e != nil {
 			err = fmt.Errorf("%s\ncannot truncate %s: %v", err, v.dataFile.Name(), e)
 		}
 		return
 	}
+	v.dataFileSize += actualSize
+
 	nv, ok := v.nm.Get(n.Id)
 	if !ok || int64(nv.Offset)*NeedlePaddingSize < offset {
 		if err = v.nm.Put(n.Id, uint32(offset/NeedlePaddingSize), n.Size); err != nil {
@@ -128,16 +137,20 @@ func (v *Volume) deleteNeedle(n *Needle) (uint32, error) {
 	defer v.dataFileAccessLock.Unlock()
 	nv, ok := v.nm.Get(n.Id)
 	//fmt.Println("key", n.Id, "volume offset", nv.Offset, "data_size", n.Size, "cached size", nv.Size)
-	if ok {
+	if ok && nv.Size != TombstoneFileSize {
 		size := nv.Size
-		if err := v.nm.Delete(n.Id); err != nil {
+		// println("adding tombstone", n.Id, "at offset", v.dataFileSize)
+		if err := v.nm.Delete(n.Id, uint32(v.dataFileSize/NeedlePaddingSize)); err != nil {
 			return size, err
 		}
-		if _, err := v.dataFile.Seek(0, 2); err != nil {
+		if offset, err := v.dataFile.Seek(0, 2); err != nil {
 			return size, err
+		} else if offset != int64(v.dataFileSize) {
+			glog.V(0).Infof("dataFileSize %d != actual data file size: %d, deleteMarker: %d", v.dataFileSize, offset, getActualSize(0))
 		}
 		n.Data = nil
-		_, err := n.Append(v.dataFile, v.Version())
+		_, actualSize, err := n.Append(v.dataFile, v.Version())
+		v.dataFileSize += actualSize
 		return size, err
 	}
 	return 0, nil
@@ -149,6 +162,9 @@ func (v *Volume) readNeedle(n *Needle) (int, error) {
 	if !ok || nv.Offset == 0 {
 		return -1, errors.New("Not Found")
 	}
+	if nv.Size == TombstoneFileSize {
+		return -1, errors.New("Already Deleted")
+	}
 	err := n.ReadData(v.dataFile, int64(nv.Offset)*NeedlePaddingSize, nv.Size, v.Version())
 	if err != nil {
 		return 0, err
diff --git a/weed/storage/volume_super_block.go b/weed/storage/volume_super_block.go
index fc773273d..ae6ee7c25 100644
--- a/weed/storage/volume_super_block.go
+++ b/weed/storage/volume_super_block.go
@@ -56,6 +56,7 @@ func (v *Volume) maybeWriteSuperBlock() error {
 				}
 			}
 		}
+		v.dataFileSize = SuperBlockSize
 	}
 	return e
 }
diff --git a/weed/storage/volume_sync.go b/weed/storage/volume_sync.go
index 7448b856f..23d8db510 100644
--- a/weed/storage/volume_sync.go
+++ b/weed/storage/volume_sync.go
@@ -148,7 +148,7 @@ func fetchVolumeFileEntries(volumeServer string, vid VolumeId) (m CompactMap, la
 	total := 0
 	err = operation.GetVolumeIdxEntries(volumeServer, vid.String(), func(key uint64, offset, size uint32) {
 		// println("remote key", key, "offset", offset*NeedlePaddingSize, "size", size)
-		if offset != 0 && size != 0 {
+		if offset > 0 && size != TombstoneFileSize {
 			m.Set(Key(key), offset, size)
 		} else {
 			m.Delete(Key(key))
diff --git a/weed/storage/volume_vacuum.go b/weed/storage/volume_vacuum.go
index 723300557..f3ded5ff2 100644
--- a/weed/storage/volume_vacuum.go
+++ b/weed/storage/volume_vacuum.go
@@ -35,7 +35,7 @@ func (v *Volume) Compact2() error {
 }
 
 func (v *Volume) commitCompact() error {
-	glog.V(3).Infof("Committing vacuuming...")
+	glog.V(0).Infof("Committing vacuuming...")
 	v.dataFileAccessLock.Lock()
 	defer v.dataFileAccessLock.Unlock()
 	glog.V(3).Infof("Got Committing lock...")
@@ -189,7 +189,7 @@ func (v *Volume) makeupDiff(newDatFileName, newIdxFileName, oldDatFileName, oldI
 				fakeDelNeedle := new(Needle)
 				fakeDelNeedle.Id = key
 				fakeDelNeedle.Cookie = 0x12345678
-				_, err = fakeDelNeedle.Append(dst, v.Version())
+				_, _, err = fakeDelNeedle.Append(dst, v.Version())
 				if err != nil {
 					return
 				}
@@ -241,7 +241,7 @@ func (v *Volume) copyDataAndGenerateIndexFile(dstName, idxName string) (err erro
 				if err = nm.Put(n.Id, uint32(new_offset/NeedlePaddingSize), n.Size); err != nil {
 					return fmt.Errorf("cannot put needle: %s", err)
 				}
-				if _, err = n.Append(dst, v.Version()); err != nil {
+				if _, _, err := n.Append(dst, v.Version()); err != nil {
 					return fmt.Errorf("cannot append needle: %s", err)
 				}
 				new_offset += n.DiskSize()
@@ -280,7 +280,7 @@ func (v *Volume) copyDataBasedOnIndexFile(dstName, idxName string) (err error) {
 	new_offset := int64(SuperBlockSize)
 
 	WalkIndexFile(oldIndexFile, func(key uint64, offset, size uint32) error {
-		if size <= 0 {
+		if offset == 0 || size == TombstoneFileSize {
 			return nil
 		}
 
@@ -302,7 +302,7 @@ func (v *Volume) copyDataBasedOnIndexFile(dstName, idxName string) (err error) {
 			if err = nm.Put(n.Id, uint32(new_offset/NeedlePaddingSize), n.Size); err != nil {
 				return fmt.Errorf("cannot put needle: %s", err)
 			}
-			if _, err = n.Append(dst, v.Version()); err != nil {
+			if _, _, err = n.Append(dst, v.Version()); err != nil {
 				return fmt.Errorf("cannot append needle: %s", err)
 			}
 			new_offset += n.DiskSize()