diff --git a/weed-fs/src/cmd/weed/fix.go b/weed-fs/src/cmd/weed/fix.go
index dfb6969eb..0b9088f32 100644
--- a/weed-fs/src/cmd/weed/fix.go
+++ b/weed-fs/src/cmd/weed/fix.go
@@ -52,10 +52,10 @@ func runFix(cmd *Command, args []string) bool {
   offset := uint32(storage.SuperBlockSize)
   for n != nil {
     if *IsDebug {
-      log.Println("key", n.Key, "volume offset", offset, "data_size", n.Size, "length", length)
+      log.Println("key", n.Id, "volume offset", offset, "data_size", n.Size, "length", length)
     }
     if n.Size > 0 {
-      count, pe := nm.Put(n.Key, offset/8, n.Size)
+      count, pe := nm.Put(n.Id, offset/8, n.Size)
       if *IsDebug {
         log.Println("saved", count, "with error", pe)
       }
diff --git a/weed-fs/src/pkg/storage/needle.go b/weed-fs/src/pkg/storage/needle.go
index 6396b8ef0..ea3cbfb1d 100644
--- a/weed-fs/src/pkg/storage/needle.go
+++ b/weed-fs/src/pkg/storage/needle.go
@@ -15,7 +15,7 @@ import (
 
 type Needle struct {
 	Cookie   uint32 "random number to mitigate brute force lookups"
-	Key      uint64 "file id"
+	Id       uint64 "needle id"
 	Size     uint32 "Data size"
 	Data     []byte "The actual file data"
 	Checksum int32  "CRC32 to check integrity"
@@ -69,18 +69,18 @@ func (n *Needle) ParsePath(fid string) {
 	if deltaIndex > 0 {
 		fid, delta = fid[0:deltaIndex], fid[deltaIndex+1:]
 	}
-	n.Key, n.Cookie = ParseKeyHash(fid)
+	n.Id, n.Cookie = ParseKeyHash(fid)
 	if delta != "" {
 		d, e := strconv.ParseUint(delta, 10, 64)
 		if e == nil {
-			n.Key += d
+			n.Id += d
 		}
 	}
 }
 func (n *Needle) Append(w io.Writer) uint32 {
 	header := make([]byte, 16)
 	util.Uint32toBytes(header[0:4], n.Cookie)
-	util.Uint64toBytes(header[4:12], n.Key)
+	util.Uint64toBytes(header[4:12], n.Id)
 	n.Size = uint32(len(n.Data))
 	util.Uint32toBytes(header[12:16], n.Size)
 	w.Write(header)
@@ -94,7 +94,7 @@ func (n *Needle) Read(r io.Reader, size uint32) (int, error) {
 	bytes := make([]byte, size+16+4)
 	ret, e := r.Read(bytes)
 	n.Cookie = util.BytesToUint32(bytes[0:4])
-	n.Key = util.BytesToUint64(bytes[4:12])
+	n.Id = util.BytesToUint64(bytes[4:12])
 	n.Size = util.BytesToUint32(bytes[12:16])
 	n.Data = bytes[16 : 16+size]
 	n.Checksum = int32(util.BytesToUint32(bytes[16+size : 16+size+4]))
@@ -108,7 +108,7 @@ func ReadNeedle(r *os.File) (*Needle, uint32) {
 		return nil, 0
 	}
 	n.Cookie = util.BytesToUint32(bytes[0:4])
-	n.Key = util.BytesToUint64(bytes[4:12])
+	n.Id = util.BytesToUint64(bytes[4:12])
 	n.Size = util.BytesToUint32(bytes[12:16])
 	rest := 8 - ((n.Size + 16 + 4) % 8)
 	r.Seek(int64(n.Size+4+rest), 1)
diff --git a/weed-fs/src/pkg/storage/volume.go b/weed-fs/src/pkg/storage/volume.go
index 55e389029..2f156a13b 100644
--- a/weed-fs/src/pkg/storage/volume.go
+++ b/weed-fs/src/pkg/storage/volume.go
@@ -76,19 +76,19 @@ func (v *Volume) write(n *Needle) uint32 {
 	defer v.accessLock.Unlock()
 	offset, _ := v.dataFile.Seek(0, 2)
 	ret := n.Append(v.dataFile)
-	nv, ok := v.nm.Get(n.Key)
+	nv, ok := v.nm.Get(n.Id)
 	if !ok || int64(nv.Offset)*8 < offset {
-		v.nm.Put(n.Key, uint32(offset/8), n.Size)
+		v.nm.Put(n.Id, uint32(offset/8), n.Size)
 	}
 	return ret
 }
 func (v *Volume) delete(n *Needle) uint32 {
 	v.accessLock.Lock()
 	defer v.accessLock.Unlock()
-	nv, ok := v.nm.Get(n.Key)
-	//log.Println("key", n.Key, "volume offset", nv.Offset, "data_size", n.Size, "cached size", nv.Size)
+	nv, ok := v.nm.Get(n.Id)
+	//log.Println("key", n.Id, "volume offset", nv.Offset, "data_size", n.Size, "cached size", nv.Size)
 	if ok {
-		v.nm.Delete(n.Key)
+		v.nm.Delete(n.Id)
 		v.dataFile.Seek(int64(nv.Offset*8), 0)
 		n.Append(v.dataFile)
 		return nv.Size
@@ -98,7 +98,7 @@ func (v *Volume) delete(n *Needle) uint32 {
 func (v *Volume) read(n *Needle) (int, error) {
 	v.accessLock.Lock()
 	defer v.accessLock.Unlock()
-	nv, ok := v.nm.Get(n.Key)
+	nv, ok := v.nm.Get(n.Id)
 	if ok && nv.Offset > 0 {
 		v.dataFile.Seek(int64(nv.Offset)*8, 0)
 		return n.Read(v.dataFile, nv.Size)