36 files changed, 162 insertions, 219 deletions

diff --git a/weed/storage/disk_location.go b/weed/storage/disk_location.go
index cd81b2210..680cc6097 100644
--- a/weed/storage/disk_location.go
+++ b/weed/storage/disk_location.go
@@ -9,22 +9,23 @@ import (
 	"fmt"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 )
 
 type DiskLocation struct {
 	Directory      string
 	MaxVolumeCount int
-	volumes        map[VolumeId]*Volume
+	volumes        map[needle.VolumeId]*Volume
 	sync.RWMutex
 }
 
 func NewDiskLocation(dir string, maxVolumeCount int) *DiskLocation {
 	location := &DiskLocation{Directory: dir, MaxVolumeCount: maxVolumeCount}
-	location.volumes = make(map[VolumeId]*Volume)
+	location.volumes = make(map[needle.VolumeId]*Volume)
 	return location
 }
 
-func (l *DiskLocation) volumeIdFromPath(dir os.FileInfo) (VolumeId, string, error) {
+func (l *DiskLocation) volumeIdFromPath(dir os.FileInfo) (needle.VolumeId, string, error) {
 	name := dir.Name()
 	if !dir.IsDir() && strings.HasSuffix(name, ".dat") {
 		collection := ""
@@ -33,7 +34,7 @@ func (l *DiskLocation) volumeIdFromPath(dir os.FileInfo) (VolumeId, string, erro
 		if i > 0 {
 			collection, base = base[0:i], base[i+1:]
 		}
-		vol, err := NewVolumeId(base)
+		vol, err := needle.NewVolumeId(base)
 		return vol, collection, err
 	}
 
@@ -114,7 +115,7 @@ func (l *DiskLocation) DeleteCollectionFromDiskLocation(collection string) (e er
 	return
 }
 
-func (l *DiskLocation) deleteVolumeById(vid VolumeId) (e error) {
+func (l *DiskLocation) deleteVolumeById(vid needle.VolumeId) (e error) {
 	v, ok := l.volumes[vid]
 	if !ok {
 		return
@@ -127,7 +128,7 @@ func (l *DiskLocation) deleteVolumeById(vid VolumeId) (e error) {
 	return
 }
 
-func (l *DiskLocation) LoadVolume(vid VolumeId, needleMapKind NeedleMapType) bool {
+func (l *DiskLocation) LoadVolume(vid needle.VolumeId, needleMapKind NeedleMapType) bool {
 	if dirs, err := ioutil.ReadDir(l.Directory); err == nil {
 		for _, dir := range dirs {
 			volId, _, err := l.volumeIdFromPath(dir)
@@ -142,7 +143,7 @@ func (l *DiskLocation) LoadVolume(vid VolumeId, needleMapKind NeedleMapType) boo
 	return false
 }
 
-func (l *DiskLocation) DeleteVolume(vid VolumeId) error {
+func (l *DiskLocation) DeleteVolume(vid needle.VolumeId) error {
 	l.Lock()
 	defer l.Unlock()
 
@@ -153,7 +154,7 @@ func (l *DiskLocation) DeleteVolume(vid VolumeId) error {
 	return l.deleteVolumeById(vid)
 }
 
-func (l *DiskLocation) UnloadVolume(vid VolumeId) error {
+func (l *DiskLocation) UnloadVolume(vid needle.VolumeId) error {
 	l.Lock()
 	defer l.Unlock()
 
@@ -166,14 +167,14 @@ func (l *DiskLocation) UnloadVolume(vid VolumeId) error {
 	return nil
 }
 
-func (l *DiskLocation) SetVolume(vid VolumeId, volume *Volume) {
+func (l *DiskLocation) SetVolume(vid needle.VolumeId, volume *Volume) {
 	l.Lock()
 	defer l.Unlock()
 
 	l.volumes[vid] = volume
 }
 
-func (l *DiskLocation) FindVolume(vid VolumeId) (*Volume, bool) {
+func (l *DiskLocation) FindVolume(vid needle.VolumeId) (*Volume, bool) {
 	l.RLock()
 	defer l.RUnlock()
 
diff --git a/weed/storage/crc.go b/weed/storage/needle/crc.go
index e49686dc8..00ea1db69 100644
--- a/weed/storage/crc.go
+++ b/weed/storage/needle/crc.go
@@ -1,4 +1,4 @@
-package storage
+package needle
 
 import (
 	"crypto/md5"
diff --git a/weed/storage/file_id.go b/weed/storage/needle/file_id.go
index 37dcb7c70..906877b8c 100644
--- a/weed/storage/file_id.go
+++ b/weed/storage/needle/file_id.go
@@ -1,7 +1,8 @@
-package storage
+package needle
 
 import (
 	"encoding/hex"
+
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 )
 
diff --git a/weed/storage/needle.go b/weed/storage/needle/needle.go
index 5bd6f7d96..c224d2767 100644
--- a/weed/storage/needle.go
+++ b/weed/storage/needle/needle.go
@@ -1,4 +1,4 @@
-package storage
+package needle
 
 import (
 	"encoding/json"
@@ -8,9 +8,10 @@ import (
 	"strings"
 	"time"
 
+	"io/ioutil"
+
 	"github.com/chrislusf/seaweedfs/weed/images"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
-	"io/ioutil"
 )
 
 const (
@@ -187,3 +188,4 @@ func ParseNeedleIdCookie(key_hash_string string) (NeedleId, Cookie, error) {
 func (n *Needle) LastModifiedString() string {
 	return time.Unix(int64(n.LastModified), 0).Format("2006-01-02T15:04:05")
 }
+
diff --git a/weed/storage/needle_parse_multipart.go b/weed/storage/needle/needle_parse_multipart.go
index 93b4c2dce..8be1a1da4 100644
--- a/weed/storage/needle_parse_multipart.go
+++ b/weed/storage/needle/needle_parse_multipart.go
@@ -1,8 +1,9 @@
-package storage
+package needle
 
 import (
 	"github.com/chrislusf/seaweedfs/weed/glog"
-	"github.com/chrislusf/seaweedfs/weed/operation"
+	"github.com/chrislusf/seaweedfs/weed/util"
+
 	"io"
 	"io/ioutil"
 	"mime"
@@ -90,12 +91,12 @@ func parseMultipart(r *http.Request) (
 		}
 
 		if part.Header.Get("Content-Encoding") == "gzip" {
-			if unzipped, e := operation.UnGzipData(data); e == nil {
+			if unzipped, e := util.UnGzipData(data); e == nil {
 				originalDataSize = len(unzipped)
 			}
 			isGzipped = true
-		} else if operation.IsGzippable(ext, mtype, data) {
-			if compressedData, err := operation.GzipData(data); err == nil {
+		} else if util.IsGzippable(ext, mtype, data) {
+			if compressedData, err := util.GzipData(data); err == nil {
 				if len(data) > len(compressedData) {
 					data = compressedData
 					isGzipped = true
diff --git a/weed/storage/needle_read_write.go b/weed/storage/needle/needle_read_write.go
index 1a2c99450..9876b2f1c 100644
--- a/weed/storage/needle_read_write.go
+++ b/weed/storage/needle/needle_read_write.go
@@ -1,4 +1,4 @@
-package storage
+package needle
 
 import (
 	"errors"
@@ -6,10 +6,11 @@ import (
 	"io"
 	"os"
 
+	"math"
+
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 	"github.com/chrislusf/seaweedfs/weed/util"
-	"math"
 )
 
 const (
@@ -383,3 +384,8 @@ func (n *Needle) HasPairs() bool {
 func (n *Needle) SetHasPairs() {
 	n.Flags = n.Flags | FlagHasPairs
 }
+
+func getActualSize(size uint32, version Version) int64 {
+	return NeedleEntrySize + NeedleBodyLength(size, version)
+}
+
diff --git a/weed/storage/needle_read_write_test.go b/weed/storage/needle/needle_read_write_test.go
index 2532e6a38..4c507f9e6 100644
--- a/weed/storage/needle_read_write_test.go
+++ b/weed/storage/needle/needle_read_write_test.go
@@ -1,10 +1,11 @@
-package storage
+package needle
 
 import (
-	"github.com/chrislusf/seaweedfs/weed/storage/types"
 	"io/ioutil"
 	"os"
 	"testing"
+
+	"github.com/chrislusf/seaweedfs/weed/storage/types"
 )
 
 func TestAppend(t *testing.T) {
diff --git a/weed/storage/needle_test.go b/weed/storage/needle/needle_test.go
index 65036409c..0f2dde98e 100644
--- a/weed/storage/needle_test.go
+++ b/weed/storage/needle/needle_test.go
@@ -1,8 +1,9 @@
-package storage
+package needle
 
 import (
-	"github.com/chrislusf/seaweedfs/weed/storage/types"
 	"testing"
+
+	"github.com/chrislusf/seaweedfs/weed/storage/types"
 )
 
 func TestParseKeyHash(t *testing.T) {
diff --git a/weed/storage/volume_id.go b/weed/storage/needle/volume_id.go
index 0333c6cf0..be56e42fa 100644
--- a/weed/storage/volume_id.go
+++ b/weed/storage/needle/volume_id.go
@@ -1,4 +1,4 @@
-package storage
+package needle
 
 import (
 	"strconv"
diff --git a/weed/storage/volume_ttl.go b/weed/storage/needle/volume_ttl.go
index 0989e7a49..0b4c9579b 100644
--- a/weed/storage/volume_ttl.go
+++ b/weed/storage/needle/volume_ttl.go
@@ -1,4 +1,4 @@
-package storage
+package needle
 
 import (
 	"strconv"
diff --git a/weed/storage/volume_ttl_test.go b/weed/storage/needle/volume_ttl_test.go
index 216469a4c..0afebebf5 100644
--- a/weed/storage/volume_ttl_test.go
+++ b/weed/storage/needle/volume_ttl_test.go
@@ -1,4 +1,4 @@
-package storage
+package needle
 
 import (
 	"testing"
diff --git a/weed/storage/volume_version.go b/weed/storage/needle/volume_version.go
index fc0270c03..54daac77f 100644
--- a/weed/storage/volume_version.go
+++ b/weed/storage/needle/volume_version.go
@@ -1,4 +1,4 @@
-package storage
+package needle
 
 type Version uint8
 
diff --git a/weed/storage/needle_byte_cache.go b/weed/storage/needle_byte_cache.go
deleted file mode 100644
index 78c1ea862..000000000
--- a/weed/storage/needle_byte_cache.go
+++ /dev/null
@@ -1,11 +0,0 @@
-package storage
-
-import (
-	"os"
-)
-
-func getBytesForFileBlock(r *os.File, offset int64, readSize int) (dataSlice []byte, err error) {
-	dataSlice = make([]byte, readSize)
-	_, err = r.ReadAt(dataSlice, offset)
-	return dataSlice, err
-}
diff --git a/weed/storage/needle_map.go b/weed/storage/needle_map.go
index 56dbd7c06..a22125682 100644
--- a/weed/storage/needle_map.go
+++ b/weed/storage/needle_map.go
@@ -6,7 +6,7 @@ import (
 	"os"
 	"sync"
 
-	"github.com/chrislusf/seaweedfs/weed/storage/needle"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle_map"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 	"github.com/chrislusf/seaweedfs/weed/util"
 )
@@ -22,7 +22,7 @@ const (
 
 type NeedleMapper interface {
 	Put(key NeedleId, offset Offset, size uint32) error
-	Get(key NeedleId) (element *needle.NeedleValue, ok bool)
+	Get(key NeedleId) (element *needle_map.NeedleValue, ok bool)
 	Delete(key NeedleId, offset Offset) error
 	Close()
 	Destroy() error
diff --git a/weed/storage/needle/btree_map.go b/weed/storage/needle_map/btree_map.go
index aed940f0e..74b4952b7 100644
--- a/weed/storage/needle/btree_map.go
+++ b/weed/storage/needle_map/btree_map.go
@@ -1,4 +1,4 @@
-package needle
+package needle_map
 
 import (
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
diff --git a/weed/storage/needle/compact_map.go b/weed/storage/needle_map/compact_map.go
index a15035961..193d17e47 100644
--- a/weed/storage/needle/compact_map.go
+++ b/weed/storage/needle_map/compact_map.go
@@ -1,4 +1,4 @@
-package needle
+package needle_map
 
 import (
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
diff --git a/weed/storage/needle/compact_map_perf_test.go b/weed/storage/needle_map/compact_map_perf_test.go
index 3f6fe548b..a447375a4 100644
--- a/weed/storage/needle/compact_map_perf_test.go
+++ b/weed/storage/needle_map/compact_map_perf_test.go
@@ -1,4 +1,4 @@
-package needle
+package needle_map
 
 import (
 	"fmt"
diff --git a/weed/storage/needle/compact_map_test.go b/weed/storage/needle_map/compact_map_test.go
index b9586ab54..4894e59ad 100644
--- a/weed/storage/needle/compact_map_test.go
+++ b/weed/storage/needle_map/compact_map_test.go
@@ -1,4 +1,4 @@
-package needle
+package needle_map
 
 import (
 	"fmt"
diff --git a/weed/storage/needle/needle_value.go b/weed/storage/needle_map/needle_value.go
index 96ee83009..d0c0b9006 100644
--- a/weed/storage/needle/needle_value.go
+++ b/weed/storage/needle_map/needle_value.go
@@ -1,4 +1,4 @@
-package needle
+package needle_map
 
 import (
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
diff --git a/weed/storage/needle/needle_value_map.go b/weed/storage/needle_map/needle_value_map.go
index 9da257443..acf38a4bf 100644
--- a/weed/storage/needle/needle_value_map.go
+++ b/weed/storage/needle_map/needle_value_map.go
@@ -1,4 +1,4 @@
-package needle
+package needle_map
 
 import (
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
diff --git a/weed/storage/needle_map_leveldb.go b/weed/storage/needle_map_leveldb.go
index 4d5280938..01807595b 100644
--- a/weed/storage/needle_map_leveldb.go
+++ b/weed/storage/needle_map_leveldb.go
@@ -7,7 +7,7 @@ import (
 	"path/filepath"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
-	"github.com/chrislusf/seaweedfs/weed/storage/needle"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle_map"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 	"github.com/chrislusf/seaweedfs/weed/util"
 	"github.com/syndtr/goleveldb/leveldb"
@@ -74,7 +74,7 @@ func generateLevelDbFile(dbFileName string, indexFile *os.File) error {
 	})
 }
 
-func (m *LevelDbNeedleMap) Get(key NeedleId) (element *needle.NeedleValue, ok bool) {
+func (m *LevelDbNeedleMap) Get(key NeedleId) (element *needle_map.NeedleValue, ok bool) {
 	bytes := make([]byte, NeedleIdSize)
 	NeedleIdToBytes(bytes[0:NeedleIdSize], key)
 	data, err := m.db.Get(bytes, nil)
@@ -83,7 +83,7 @@ func (m *LevelDbNeedleMap) Get(key NeedleId) (element *needle.NeedleValue, ok bo
 	}
 	offset := BytesToOffset(data[0:OffsetSize])
 	size := util.BytesToUint32(data[OffsetSize : OffsetSize+SizeSize])
-	return &needle.NeedleValue{Key: NeedleId(key), Offset: offset, Size: size}, true
+	return &needle_map.NeedleValue{Key: NeedleId(key), Offset: offset, Size: size}, true
 }
 
 func (m *LevelDbNeedleMap) Put(key NeedleId, offset Offset, size uint32) error {
diff --git a/weed/storage/needle_map_memory.go b/weed/storage/needle_map_memory.go
index a3b574324..060920cea 100644
--- a/weed/storage/needle_map_memory.go
+++ b/weed/storage/needle_map_memory.go
@@ -5,19 +5,19 @@ import (
 	"os"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
-	"github.com/chrislusf/seaweedfs/weed/storage/needle"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle_map"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 )
 
 type NeedleMap struct {
-	m needle.NeedleValueMap
+	m needle_map.NeedleValueMap
 
 	baseNeedleMapper
 }
 
 func NewCompactNeedleMap(file *os.File) *NeedleMap {
 	nm := &NeedleMap{
-		m: needle.NewCompactMap(),
+		m: needle_map.NewCompactMap(),
 	}
 	nm.indexFile = file
 	return nm
@@ -25,7 +25,7 @@ func NewCompactNeedleMap(file *os.File) *NeedleMap {
 
 func NewBtreeNeedleMap(file *os.File) *NeedleMap {
 	nm := &NeedleMap{
-		m: needle.NewBtreeMap(),
+		m: needle_map.NewBtreeMap(),
 	}
 	nm.indexFile = file
 	return nm
@@ -106,7 +106,7 @@ func (nm *NeedleMap) Put(key NeedleId, offset Offset, size uint32) error {
 	nm.logPut(key, oldSize, size)
 	return nm.appendToIndexFile(key, offset, size)
 }
-func (nm *NeedleMap) Get(key NeedleId) (element *needle.NeedleValue, ok bool) {
+func (nm *NeedleMap) Get(key NeedleId) (element *needle_map.NeedleValue, ok bool) {
 	element, ok = nm.m.Get(NeedleId(key))
 	return
 }
diff --git a/weed/storage/store.go b/weed/storage/store.go
index d866d2e11..3c222c0aa 100644
--- a/weed/storage/store.go
+++ b/weed/storage/store.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 )
 
@@ -27,8 +28,8 @@ type Store struct {
 	volumeSizeLimit     uint64 //read from the master
 	Client              master_pb.Seaweed_SendHeartbeatClient
 	NeedleMapType       NeedleMapType
-	NewVolumeIdChan     chan VolumeId
-	DeletedVolumeIdChan chan VolumeId
+	NewVolumeIdChan     chan needle.VolumeId
+	DeletedVolumeIdChan chan needle.VolumeId
 }
 
 func (s *Store) String() (str string) {
@@ -44,16 +45,16 @@ func NewStore(port int, ip, publicUrl string, dirnames []string, maxVolumeCounts
 		location.loadExistingVolumes(needleMapKind)
 		s.Locations = append(s.Locations, location)
 	}
-	s.NewVolumeIdChan = make(chan VolumeId, 3)
-	s.DeletedVolumeIdChan = make(chan VolumeId, 3)
+	s.NewVolumeIdChan = make(chan needle.VolumeId, 3)
+	s.DeletedVolumeIdChan = make(chan needle.VolumeId, 3)
 	return
 }
-func (s *Store) AddVolume(volumeId VolumeId, collection string, needleMapKind NeedleMapType, replicaPlacement string, ttlString string, preallocate int64) error {
+func (s *Store) AddVolume(volumeId needle.VolumeId, collection string, needleMapKind NeedleMapType, replicaPlacement string, ttlString string, preallocate int64) error {
 	rt, e := NewReplicaPlacementFromString(replicaPlacement)
 	if e != nil {
 		return e
 	}
-	ttl, e := ReadTTL(ttlString)
+	ttl, e := needle.ReadTTL(ttlString)
 	if e != nil {
 		return e
 	}
@@ -71,7 +72,7 @@ func (s *Store) DeleteCollection(collection string) (e error) {
 	return
 }
 
-func (s *Store) findVolume(vid VolumeId) *Volume {
+func (s *Store) findVolume(vid needle.VolumeId) *Volume {
 	for _, location := range s.Locations {
 		if v, found := location.FindVolume(vid); found {
 			return v
@@ -90,7 +91,7 @@ func (s *Store) FindFreeLocation() (ret *DiskLocation) {
 	}
 	return ret
 }
-func (s *Store) addVolume(vid VolumeId, collection string, needleMapKind NeedleMapType, replicaPlacement *ReplicaPlacement, ttl *TTL, preallocate int64) error {
+func (s *Store) addVolume(vid needle.VolumeId, collection string, needleMapKind NeedleMapType, replicaPlacement *ReplicaPlacement, ttl *needle.TTL, preallocate int64) error {
 	if s.findVolume(vid) != nil {
 		return fmt.Errorf("Volume Id %d already exists!", vid)
 	}
@@ -114,7 +115,7 @@ func (s *Store) Status() []*VolumeInfo {
 		location.RLock()
 		for k, v := range location.volumes {
 			s := &VolumeInfo{
-				Id:               VolumeId(k),
+				Id:               needle.VolumeId(k),
 				Size:             v.ContentSize(),
 				Collection:       v.Collection,
 				ReplicaPlacement: v.ReplicaPlacement,
@@ -184,7 +185,7 @@ func (s *Store) Close() {
 	}
 }
 
-func (s *Store) Write(i VolumeId, n *Needle) (size uint32, err error) {
+func (s *Store) Write(i needle.VolumeId, n *needle.Needle) (size uint32, err error) {
 	if v := s.findVolume(i); v != nil {
 		if v.readOnly {
 			err = fmt.Errorf("Volume %d is read only", i)
@@ -203,32 +204,32 @@ func (s *Store) Write(i VolumeId, n *Needle) (size uint32, err error) {
 	return
 }
 
-func (s *Store) Delete(i VolumeId, n *Needle) (uint32, error) {
+func (s *Store) Delete(i needle.VolumeId, n *needle.Needle) (uint32, error) {
 	if v := s.findVolume(i); v != nil && !v.readOnly {
 		return v.deleteNeedle(n)
 	}
 	return 0, nil
 }
 
-func (s *Store) ReadVolumeNeedle(i VolumeId, n *Needle) (int, error) {
+func (s *Store) ReadVolumeNeedle(i needle.VolumeId, n *needle.Needle) (int, error) {
 	if v := s.findVolume(i); v != nil {
 		return v.readNeedle(n)
 	}
 	return 0, fmt.Errorf("Volume %d not found!", i)
 }
-func (s *Store) GetVolume(i VolumeId) *Volume {
+func (s *Store) GetVolume(i needle.VolumeId) *Volume {
 	return s.findVolume(i)
 }
 
-func (s *Store) HasVolume(i VolumeId) bool {
+func (s *Store) HasVolume(i needle.VolumeId) bool {
 	v := s.findVolume(i)
 	return v != nil
 }
 
-func (s *Store) MountVolume(i VolumeId) error {
+func (s *Store) MountVolume(i needle.VolumeId) error {
 	for _, location := range s.Locations {
 		if found := location.LoadVolume(i, s.NeedleMapType); found == true {
-			s.NewVolumeIdChan <- VolumeId(i)
+			s.NewVolumeIdChan <- needle.VolumeId(i)
 			return nil
 		}
 	}
@@ -236,10 +237,10 @@ func (s *Store) MountVolume(i VolumeId) error {
 	return fmt.Errorf("Volume %d not found on disk", i)
 }
 
-func (s *Store) UnmountVolume(i VolumeId) error {
+func (s *Store) UnmountVolume(i needle.VolumeId) error {
 	for _, location := range s.Locations {
 		if err := location.UnloadVolume(i); err == nil {
-			s.DeletedVolumeIdChan <- VolumeId(i)
+			s.DeletedVolumeIdChan <- needle.VolumeId(i)
 			return nil
 		}
 	}
@@ -247,10 +248,10 @@ func (s *Store) UnmountVolume(i VolumeId) error {
 	return fmt.Errorf("Volume %d not found on disk", i)
 }
 
-func (s *Store) DeleteVolume(i VolumeId) error {
+func (s *Store) DeleteVolume(i needle.VolumeId) error {
 	for _, location := range s.Locations {
 		if error := location.deleteVolumeById(i); error == nil {
-			s.DeletedVolumeIdChan <- VolumeId(i)
+			s.DeletedVolumeIdChan <- needle.VolumeId(i)
 			return nil
 		}
 	}
diff --git a/weed/storage/store_vacuum.go b/weed/storage/store_vacuum.go
index 0036315c8..5f982a8c3 100644
--- a/weed/storage/store_vacuum.go
+++ b/weed/storage/store_vacuum.go
@@ -2,29 +2,31 @@ package storage
 
 import (
 	"fmt"
+
 	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 )
 
-func (s *Store) CheckCompactVolume(volumeId VolumeId) (float64, error) {
+func (s *Store) CheckCompactVolume(volumeId needle.VolumeId) (float64, error) {
 	if v := s.findVolume(volumeId); v != nil {
 		glog.V(3).Infof("volumd %d garbage level: %f", volumeId, v.garbageLevel())
 		return v.garbageLevel(), nil
 	}
 	return 0, fmt.Errorf("volume id %d is not found during check compact", volumeId)
 }
-func (s *Store) CompactVolume(vid VolumeId, preallocate int64) error {
+func (s *Store) CompactVolume(vid needle.VolumeId, preallocate int64) error {
 	if v := s.findVolume(vid); v != nil {
 		return v.Compact(preallocate)
 	}
 	return fmt.Errorf("volume id %d is not found during compact", vid)
 }
-func (s *Store) CommitCompactVolume(vid VolumeId) error {
+func (s *Store) CommitCompactVolume(vid needle.VolumeId) error {
 	if v := s.findVolume(vid); v != nil {
 		return v.CommitCompact()
 	}
 	return fmt.Errorf("volume id %d is not found during commit compact", vid)
 }
-func (s *Store) CommitCleanupVolume(vid VolumeId) error {
+func (s *Store) CommitCleanupVolume(vid needle.VolumeId) error {
 	if v := s.findVolume(vid); v != nil {
 		return v.cleanupCompact()
 	}
diff --git a/weed/storage/tail_volume.go.go b/weed/storage/tail_volume.go.go
deleted file mode 100644
index 31ad058b1..000000000
--- a/weed/storage/tail_volume.go.go
+++ /dev/null
@@ -1,78 +0,0 @@
-package storage
-
-import (
-	"context"
-	"fmt"
-	"io"
-
-	"github.com/chrislusf/seaweedfs/weed/operation"
-	"github.com/chrislusf/seaweedfs/weed/pb/volume_server_pb"
-	"google.golang.org/grpc"
-)
-
-func TailVolume(master string, grpcDialOption grpc.DialOption, vid VolumeId, sinceNs uint64, timeoutSeconds int, fn func(n *Needle) error) error {
-	// find volume location, replication, ttl info
-	lookup, err := operation.Lookup(master, vid.String())
-	if err != nil {
-		return fmt.Errorf("look up volume %d: %v", vid, err)
-	}
-	if len(lookup.Locations) == 0 {
-		return fmt.Errorf("unable to locate volume %d", vid)
-	}
-
-	volumeServer := lookup.Locations[0].Url
-
-	return operation.WithVolumeServerClient(volumeServer, grpcDialOption, func(client volume_server_pb.VolumeServerClient) error {
-
-		stream, err := client.VolumeTail(context.Background(), &volume_server_pb.VolumeTailRequest{
-			VolumeId:        uint32(vid),
-			SinceNs:         sinceNs,
-			DrainingSeconds: uint32(timeoutSeconds),
-		})
-		if err != nil {
-			return err
-		}
-
-		for {
-			resp, recvErr := stream.Recv()
-			if recvErr != nil {
-				if recvErr == io.EOF {
-					break
-				} else {
-					return recvErr
-				}
-			}
-
-			needleHeader := resp.NeedleHeader
-			needleBody := resp.NeedleBody
-
-			if len(needleHeader) == 0 {
-				continue
-			}
-
-			for !resp.IsLastChunk {
-				resp, recvErr = stream.Recv()
-				if recvErr != nil {
-					if recvErr == io.EOF {
-						break
-					} else {
-						return recvErr
-					}
-				}
-				needleBody = append(needleBody, resp.NeedleBody...)
-			}
-
-			n := new(Needle)
-			n.ParseNeedleHeader(needleHeader)
-			n.ReadNeedleBodyBytes(needleBody, CurrentVersion)
-
-			err = fn(n)
-
-			if err != nil {
-				return err
-			}
-
-		}
-		return nil
-	})
-}
diff --git a/weed/storage/volume.go b/weed/storage/volume.go
index 54769eaca..e33d90d28 100644
--- a/weed/storage/volume.go
+++ b/weed/storage/volume.go
@@ -2,7 +2,10 @@ package storage
 
 import (
 	"fmt"
+
 	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
+
 	"os"
 	"path"
 	"strconv"
@@ -13,7 +16,7 @@ import (
 )
 
 type Volume struct {
-	Id            VolumeId
+	Id            needle.VolumeId
 	dir           string
 	Collection    string
 	dataFile      *os.File
@@ -31,7 +34,7 @@ type Volume struct {
 	lastCompactRevision    uint16
 }
 
-func NewVolume(dirname string, collection string, id VolumeId, needleMapKind NeedleMapType, replicaPlacement *ReplicaPlacement, ttl *TTL, preallocate int64) (v *Volume, e error) {
+func NewVolume(dirname string, collection string, id needle.VolumeId, needleMapKind NeedleMapType, replicaPlacement *ReplicaPlacement, ttl *needle.TTL, preallocate int64) (v *Volume, e error) {
 	// if replicaPlacement is nil, the superblock will be loaded from disk
 	v = &Volume{dir: dirname, Collection: collection, Id: id}
 	v.SuperBlock = SuperBlock{ReplicaPlacement: replicaPlacement, Ttl: ttl}
@@ -59,7 +62,7 @@ func (v *Volume) DataFile() *os.File {
 	return v.dataFile
 }
 
-func (v *Volume) Version() Version {
+func (v *Volume) Version() needle.Version {
 	return v.SuperBlock.Version()
 }
 
diff --git a/weed/storage/volume_backup.go b/weed/storage/volume_backup.go
index 9a261df71..d25f945f8 100644
--- a/weed/storage/volume_backup.go
+++ b/weed/storage/volume_backup.go
@@ -3,12 +3,14 @@ package storage
 import (
 	"context"
 	"fmt"
+	"io"
+	"os"
+
 	"github.com/chrislusf/seaweedfs/weed/operation"
 	"github.com/chrislusf/seaweedfs/weed/pb/volume_server_pb"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 	"google.golang.org/grpc"
-	"io"
-	"os"
 )
 
 func (v *Volume) GetVolumeSyncStatus() *volume_server_pb.VolumeSyncStatusResponse {
@@ -147,7 +149,7 @@ func (v *Volume) locateLastAppendEntry() (Offset, error) {
 
 func (v *Volume) readAppendAtNs(offset Offset) (uint64, error) {
 
-	n, _, bodyLength, err := ReadNeedleHeader(v.dataFile, v.SuperBlock.version, offset.ToAcutalOffset())
+	n, _, bodyLength, err := needle.ReadNeedleHeader(v.dataFile, v.SuperBlock.version, offset.ToAcutalOffset())
 	if err != nil {
 		return 0, fmt.Errorf("ReadNeedleHeader: %v", err)
 	}
@@ -245,7 +247,7 @@ func (scanner *VolumeFileScanner4GenIdx) ReadNeedleBody() bool {
 	return false
 }
 
-func (scanner *VolumeFileScanner4GenIdx) VisitNeedle(n *Needle, offset int64) error {
+func (scanner *VolumeFileScanner4GenIdx) VisitNeedle(n *needle.Needle, offset int64) error {
 	if n.Size > 0 && n.Size != TombstoneFileSize {
 		return scanner.v.nm.Put(n.Id, ToOffset(offset), n.Size)
 	}
diff --git a/weed/storage/volume_checking.go b/weed/storage/volume_checking.go
index 1ac73d3d3..0f419f2c0 100644
--- a/weed/storage/volume_checking.go
+++ b/weed/storage/volume_checking.go
@@ -4,14 +4,11 @@ import (
 	"fmt"
 	"os"
 
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 	"github.com/chrislusf/seaweedfs/weed/util"
 )
 
-func getActualSize(size uint32, version Version) int64 {
-	return NeedleEntrySize + NeedleBodyLength(size, version)
-}
-
 func CheckVolumeDataIntegrity(v *Volume, indexFile *os.File) error {
 	var indexSize int64
 	var e error
@@ -55,8 +52,8 @@ func readIndexEntryAtOffset(indexFile *os.File, offset int64) (bytes []byte, err
 	return
 }
 
-func verifyNeedleIntegrity(datFile *os.File, v Version, offset int64, key NeedleId, size uint32) error {
-	n := new(Needle)
+func verifyNeedleIntegrity(datFile *os.File, v needle.Version, offset int64, key NeedleId, size uint32) error {
+	n := new(needle.Needle)
 	err := n.ReadData(datFile, offset, size, v)
 	if err != nil {
 		return err
diff --git a/weed/storage/volume_info.go b/weed/storage/volume_info.go
index f5ddeca14..638b1e751 100644
--- a/weed/storage/volume_info.go
+++ b/weed/storage/volume_info.go
@@ -5,15 +5,16 @@ import (
 	"sort"
 
 	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 )
 
 type VolumeInfo struct {
-	Id               VolumeId
+	Id               needle.VolumeId
 	Size             uint64
 	ReplicaPlacement *ReplicaPlacement
-	Ttl              *TTL
+	Ttl              *needle.TTL
 	Collection       string
-	Version          Version
+	Version          needle.Version
 	FileCount        int
 	DeleteCount      int
 	DeletedByteCount uint64
@@ -23,14 +24,14 @@ type VolumeInfo struct {
 
 func NewVolumeInfo(m *master_pb.VolumeInformationMessage) (vi VolumeInfo, err error) {
 	vi = VolumeInfo{
-		Id:               VolumeId(m.Id),
+		Id:               needle.VolumeId(m.Id),
 		Size:             m.Size,
 		Collection:       m.Collection,
 		FileCount:        int(m.FileCount),
 		DeleteCount:      int(m.DeleteCount),
 		DeletedByteCount: m.DeletedByteCount,
 		ReadOnly:         m.ReadOnly,
-		Version:          Version(m.Version),
+		Version:          needle.Version(m.Version),
 		CompactRevision:  m.CompactRevision,
 	}
 	rp, e := NewReplicaPlacementFromByte(byte(m.ReplicaPlacement))
@@ -38,7 +39,7 @@ func NewVolumeInfo(m *master_pb.VolumeInformationMessage) (vi VolumeInfo, err er
 		return vi, e
 	}
 	vi.ReplicaPlacement = rp
-	vi.Ttl = LoadTTLFromUint32(m.Ttl)
+	vi.Ttl = needle.LoadTTLFromUint32(m.Ttl)
 	return vi, nil
 }
 
diff --git a/weed/storage/volume_info_test.go b/weed/storage/volume_info_test.go
index 9a9c43ad2..5b1bacb52 100644
--- a/weed/storage/volume_info_test.go
+++ b/weed/storage/volume_info_test.go
@@ -1,6 +1,10 @@
 package storage
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
+)
 
 func TestSortVolumeInfos(t *testing.T) {
 	vis := []*VolumeInfo{
@@ -16,7 +20,7 @@ func TestSortVolumeInfos(t *testing.T) {
 	}
 	sortVolumeInfos(vis)
 	for i := 0; i < len(vis); i++ {
-		if vis[i].Id != VolumeId(i+1) {
+		if vis[i].Id != needle.VolumeId(i+1) {
 			t.Fatal()
 		}
 	}
diff --git a/weed/storage/volume_loading.go b/weed/storage/volume_loading.go
index 14013b302..82eb98b45 100644
--- a/weed/storage/volume_loading.go
+++ b/weed/storage/volume_loading.go
@@ -2,14 +2,16 @@ package storage
 
 import (
 	"fmt"
-	"github.com/syndtr/goleveldb/leveldb/opt"
 	"os"
 	"time"
 
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+
 	"github.com/chrislusf/seaweedfs/weed/glog"
 )
 
-func loadVolumeWithoutIndex(dirname string, collection string, id VolumeId, needleMapKind NeedleMapType) (v *Volume, e error) {
+func loadVolumeWithoutIndex(dirname string, collection string, id needle.VolumeId, needleMapKind NeedleMapType) (v *Volume, e error) {
 	v = &Volume{dir: dirname, Collection: collection, Id: id}
 	v.SuperBlock = SuperBlock{}
 	v.needleMapKind = needleMapKind
diff --git a/weed/storage/volume_read_write.go b/weed/storage/volume_read_write.go
index 50ea8fecb..45888d53b 100644
--- a/weed/storage/volume_read_write.go
+++ b/weed/storage/volume_read_write.go
@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 )
 
@@ -16,13 +17,13 @@ var ErrorNotFound = errors.New("not found")
 
 // isFileUnchanged checks whether this needle to write is same as last one.
 // It requires serialized access in the same volume.
-func (v *Volume) isFileUnchanged(n *Needle) bool {
+func (v *Volume) isFileUnchanged(n *needle.Needle) bool {
 	if v.Ttl.String() != "" {
 		return false
 	}
 	nv, ok := v.nm.Get(n.Id)
 	if ok && !nv.Offset.IsZero() && nv.Size != TombstoneFileSize {
-		oldNeedle := new(Needle)
+		oldNeedle := new(needle.Needle)
 		err := oldNeedle.ReadData(v.dataFile, nv.Offset.ToAcutalOffset(), nv.Size, v.Version())
 		if err != nil {
 			glog.V(0).Infof("Failed to check updated file at offset %d size %d: %v", nv.Offset.ToAcutalOffset(), nv.Size, err)
@@ -76,8 +77,8 @@ func (v *Volume) AppendBlob(b []byte) (offset int64, err error) {
 	return
 }
 
-func (v *Volume) writeNeedle(n *Needle) (offset uint64, size uint32, err error) {
-	glog.V(4).Infof("writing needle %s", NewFileIdFromNeedle(v.Id, n).String())
+func (v *Volume) writeNeedle(n *needle.Needle) (offset uint64, size uint32, err error) {
+	glog.V(4).Infof("writing needle %s", needle.NewFileIdFromNeedle(v.Id, n).String())
 	if v.readOnly {
 		err = fmt.Errorf("%s is read-only", v.dataFile.Name())
 		return
@@ -107,8 +108,8 @@ func (v *Volume) writeNeedle(n *Needle) (offset uint64, size uint32, err error)
 	return
 }
 
-func (v *Volume) deleteNeedle(n *Needle) (uint32, error) {
-	glog.V(4).Infof("delete needle %s", NewFileIdFromNeedle(v.Id, n).String())
+func (v *Volume) deleteNeedle(n *needle.Needle) (uint32, error) {
+	glog.V(4).Infof("delete needle %s", needle.NewFileIdFromNeedle(v.Id, n).String())
 	if v.readOnly {
 		return 0, fmt.Errorf("%s is read-only", v.dataFile.Name())
 	}
@@ -133,7 +134,7 @@ func (v *Volume) deleteNeedle(n *Needle) (uint32, error) {
 }
 
 // read fills in Needle content by looking up n.Id from NeedleMapper
-func (v *Volume) readNeedle(n *Needle) (int, error) {
+func (v *Volume) readNeedle(n *needle.Needle) (int, error) {
 	nv, ok := v.nm.Get(n.Id)
 	if !ok || nv.Offset.IsZero() {
 		v.compactingWg.Wait()
@@ -172,10 +173,10 @@ func (v *Volume) readNeedle(n *Needle) (int, error) {
 type VolumeFileScanner interface {
 	VisitSuperBlock(SuperBlock) error
 	ReadNeedleBody() bool
-	VisitNeedle(n *Needle, offset int64) error
+	VisitNeedle(n *needle.Needle, offset int64) error
 }
 
-func ScanVolumeFile(dirname string, collection string, id VolumeId,
+func ScanVolumeFile(dirname string, collection string, id needle.VolumeId,
 	needleMapKind NeedleMapType,
 	volumeFileScanner VolumeFileScanner) (err error) {
 	var v *Volume
@@ -194,8 +195,8 @@ func ScanVolumeFile(dirname string, collection string, id VolumeId,
 	return ScanVolumeFileFrom(version, v.dataFile, offset, volumeFileScanner)
 }
 
-func ScanVolumeFileFrom(version Version, dataFile *os.File, offset int64, volumeFileScanner VolumeFileScanner) (err error) {
-	n, _, rest, e := ReadNeedleHeader(dataFile, version, offset)
+func ScanVolumeFileFrom(version needle.Version, dataFile *os.File, offset int64, volumeFileScanner VolumeFileScanner) (err error) {
+	n, _, rest, e := needle.ReadNeedleHeader(dataFile, version, offset)
 	if e != nil {
 		if e == io.EOF {
 			return nil
@@ -219,7 +220,7 @@ func ScanVolumeFileFrom(version Version, dataFile *os.File, offset int64, volume
 		}
 		offset += NeedleEntrySize + rest
 		glog.V(4).Infof("==> new entry offset %d", offset)
-		if n, _, rest, err = ReadNeedleHeader(dataFile, version, offset); err != nil {
+		if n, _, rest, err = needle.ReadNeedleHeader(dataFile, version, offset); err != nil {
 			if err == io.EOF {
 				return nil
 			}
@@ -230,8 +231,8 @@ func ScanVolumeFileFrom(version Version, dataFile *os.File, offset int64, volume
 	return nil
 }
 
-func ScanVolumeFileNeedleFrom(version Version, dataFile *os.File, offset int64, fn func(needleHeader, needleBody []byte, needleAppendAtNs uint64) error) (err error) {
-	n, nh, rest, e := ReadNeedleHeader(dataFile, version, offset)
+func ScanVolumeFileNeedleFrom(version needle.Version, dataFile *os.File, offset int64, fn func(needleHeader, needleBody []byte, needleAppendAtNs uint64) error) (err error) {
+	n, nh, rest, e := needle.ReadNeedleHeader(dataFile, version, offset)
 	if e != nil {
 		if e == io.EOF {
 			return nil
@@ -252,7 +253,7 @@ func ScanVolumeFileNeedleFrom(version Version, dataFile *os.File, offset int64,
 		}
 		offset += NeedleEntrySize + rest
 		glog.V(4).Infof("==> new entry offset %d", offset)
-		if n, nh, rest, err = ReadNeedleHeader(dataFile, version, offset); err != nil {
+		if n, nh, rest, err = needle.ReadNeedleHeader(dataFile, version, offset); err != nil {
 			if err == io.EOF {
 				return nil
 			}
diff --git a/weed/storage/volume_super_block.go b/weed/storage/volume_super_block.go
index 6435a051f..cdb668888 100644
--- a/weed/storage/volume_super_block.go
+++ b/weed/storage/volume_super_block.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 	"github.com/chrislusf/seaweedfs/weed/util"
 	"github.com/golang/protobuf/proto"
 )
@@ -23,9 +24,9 @@ const (
 * Rest bytes: Reserved
  */
 type SuperBlock struct {
-	version          Version
+	version          needle.Version
 	ReplicaPlacement *ReplicaPlacement
-	Ttl              *TTL
+	Ttl              *needle.TTL
 	CompactRevision  uint16
 	Extra            *master_pb.SuperBlockExtra
 	extraSize        uint16
@@ -33,13 +34,13 @@ type SuperBlock struct {
 
 func (s *SuperBlock) BlockSize() int {
 	switch s.version {
-	case Version2, Version3:
+	case needle.Version2, needle.Version3:
 		return _SuperBlockSize + int(s.extraSize)
 	}
 	return _SuperBlockSize
 }
 
-func (s *SuperBlock) Version() Version {
+func (s *SuperBlock) Version() needle.Version {
 	return s.version
 }
 func (s *SuperBlock) Bytes() []byte {
@@ -75,7 +76,7 @@ func (v *Volume) maybeWriteSuperBlock() error {
 		return e
 	}
 	if stat.Size() == 0 {
-		v.SuperBlock.version = CurrentVersion
+		v.SuperBlock.version = needle.CurrentVersion
 		_, e = v.dataFile.Write(v.SuperBlock.Bytes())
 		if e != nil && os.IsPermission(e) {
 			//read-only, but zero length - recreate it!
@@ -105,12 +106,12 @@ func ReadSuperBlock(dataFile *os.File) (superBlock SuperBlock, err error) {
 		err = fmt.Errorf("cannot read volume %s super block: %v", dataFile.Name(), e)
 		return
 	}
-	superBlock.version = Version(header[0])
+	superBlock.version = needle.Version(header[0])
 	if superBlock.ReplicaPlacement, err = NewReplicaPlacementFromByte(header[1]); err != nil {
 		err = fmt.Errorf("cannot read replica type: %s", err.Error())
 		return
 	}
-	superBlock.Ttl = LoadTTLFromBytes(header[2:4])
+	superBlock.Ttl = needle.LoadTTLFromBytes(header[2:4])
 	superBlock.CompactRevision = util.BytesToUint16(header[4:6])
 	superBlock.extraSize = util.BytesToUint16(header[6:8])
 
diff --git a/weed/storage/volume_super_block_test.go b/weed/storage/volume_super_block_test.go
index 13db4b194..06ad8a5d3 100644
--- a/weed/storage/volume_super_block_test.go
+++ b/weed/storage/volume_super_block_test.go
@@ -2,20 +2,22 @@ package storage
 
 import (
 	"testing"
+
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 )
 
 func TestSuperBlockReadWrite(t *testing.T) {
 	rp, _ := NewReplicaPlacementFromByte(byte(001))
-	ttl, _ := ReadTTL("15d")
+	ttl, _ := needle.ReadTTL("15d")
 	s := &SuperBlock{
-		version:          CurrentVersion,
+		version:          needle.CurrentVersion,
 		ReplicaPlacement: rp,
 		Ttl:              ttl,
 	}
 
 	bytes := s.Bytes()
 
-	if !(bytes[2] == 15 && bytes[3] == Day) {
+	if !(bytes[2] == 15 && bytes[3] == needle.Day) {
 		println("byte[2]:", bytes[2], "byte[3]:", bytes[3])
 		t.Fail()
 	}
diff --git a/weed/storage/volume_vacuum.go b/weed/storage/volume_vacuum.go
index b550edb80..109955bb5 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/storage/needle"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 	"github.com/chrislusf/seaweedfs/weed/util"
 )
@@ -205,7 +206,7 @@ func (v *Volume) makeupDiff(newDatFileName, newIdxFileName, oldDatFileName, oldI
 			//even the needle cache in memory is hit, the need_bytes is correct
 			glog.V(4).Infof("file %d offset %d size %d", key, increIdxEntry.offset.ToAcutalOffset(), increIdxEntry.size)
 			var needleBytes []byte
-			needleBytes, err = ReadNeedleBlob(oldDatFile, increIdxEntry.offset.ToAcutalOffset(), increIdxEntry.size, v.Version())
+			needleBytes, err = needle.ReadNeedleBlob(oldDatFile, increIdxEntry.offset.ToAcutalOffset(), increIdxEntry.size, v.Version())
 			if err != nil {
 				return fmt.Errorf("ReadNeedleBlob %s key %d offset %d size %d failed: %v", oldDatFile.Name(), key, increIdxEntry.offset.ToAcutalOffset(), increIdxEntry.size, err)
 			}
@@ -213,7 +214,7 @@ func (v *Volume) makeupDiff(newDatFileName, newIdxFileName, oldDatFileName, oldI
 			util.Uint32toBytes(idxEntryBytes[8:12], uint32(offset/NeedlePaddingSize))
 		} else { //deleted needle
 			//fakeDelNeedle 's default Data field is nil
-			fakeDelNeedle := new(Needle)
+			fakeDelNeedle := new(needle.Needle)
 			fakeDelNeedle.Id = key
 			fakeDelNeedle.Cookie = 0x12345678
 			fakeDelNeedle.AppendAtNs = uint64(time.Now().UnixNano())
@@ -235,7 +236,7 @@ func (v *Volume) makeupDiff(newDatFileName, newIdxFileName, oldDatFileName, oldI
 }
 
 type VolumeFileScanner4Vacuum struct {
-	version   Version
+	version   needle.Version
 	v         *Volume
 	dst       *os.File
 	nm        *NeedleMap
@@ -255,7 +256,7 @@ func (scanner *VolumeFileScanner4Vacuum) ReadNeedleBody() bool {
 	return true
 }
 
-func (scanner *VolumeFileScanner4Vacuum) VisitNeedle(n *Needle, offset int64) error {
+func (scanner *VolumeFileScanner4Vacuum) VisitNeedle(n *needle.Needle, offset int64) error {
 	if n.HasTtl() && scanner.now >= n.LastModified+uint64(scanner.v.Ttl.Minutes()*60) {
 		return nil
 	}
@@ -334,7 +335,7 @@ func (v *Volume) copyDataBasedOnIndexFile(dstName, idxName string) (err error) {
 			return nil
 		}
 
-		n := new(Needle)
+		n := new(needle.Needle)
 		err := n.ReadData(v.dataFile, offset.ToAcutalOffset(), size, v.Version())
 		if err != nil {
 			return nil
diff --git a/weed/storage/volume_vacuum_test.go b/weed/storage/volume_vacuum_test.go
index 4909885b9..5192d23b8 100644
--- a/weed/storage/volume_vacuum_test.go
+++ b/weed/storage/volume_vacuum_test.go
@@ -1,11 +1,13 @@
 package storage
 
 import (
-	"github.com/chrislusf/seaweedfs/weed/storage/types"
 	"io/ioutil"
 	"math/rand"
 	"os"
 	"testing"
+
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
+	"github.com/chrislusf/seaweedfs/weed/storage/types"
 )
 
 /*
@@ -65,7 +67,7 @@ func TestCompaction(t *testing.T) {
 	}
 	defer os.RemoveAll(dir) // clean up
 
-	v, err := NewVolume(dir, "", 1, NeedleMapInMemory, &ReplicaPlacement{}, &TTL{}, 0)
+	v, err := NewVolume(dir, "", 1, NeedleMapInMemory, &ReplicaPlacement{}, &needle.TTL{}, 0)
 	if err != nil {
 		t.Fatalf("volume creation: %v", err)
 	}
@@ -145,21 +147,21 @@ func doSomeWritesDeletes(i int, v *Volume, t *testing.T, infos []*needleInfo) {
 
 type needleInfo struct {
 	size uint32
-	crc  CRC
+	crc  needle.CRC
 }
 
-func newRandomNeedle(id uint64) *Needle {
-	n := new(Needle)
+func newRandomNeedle(id uint64) *needle.Needle {
+	n := new(needle.Needle)
 	n.Data = make([]byte, rand.Intn(1024))
 	rand.Read(n.Data)
 
-	n.Checksum = NewCRC(n.Data)
+	n.Checksum = needle.NewCRC(n.Data)
 	n.Id = types.Uint64ToNeedleId(id)
 	return n
 }
 
-func newEmptyNeedle(id uint64) *Needle {
-	n := new(Needle)
+func newEmptyNeedle(id uint64) *needle.Needle {
+	n := new(needle.Needle)
 	n.Id = types.Uint64ToNeedleId(id)
 	return n
 }