diff --git a/weed-fs/bin/.gitignore b/weed-fs/bin/.gitignore
deleted file mode 100644
index aa3146581..000000000
--- a/weed-fs/bin/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-/weed
diff --git a/weed-fs/src/cmd/weed/master.go b/weed-fs/src/cmd/weed/master.go
index dee94e965..6dc3b06b9 100644
--- a/weed-fs/src/cmd/weed/master.go
+++ b/weed-fs/src/cmd/weed/master.go
@@ -39,7 +39,7 @@ func dirLookupHandler(w http.ResponseWriter, r *http.Request) {
     vid = vid[0:commaSep]
   }
   volumeId, _ := strconv.ParseUint(vid, 10, 64)
-  machine, e := mapper.Get(uint32(volumeId))
+  machine, e := mapper.Get(topology.VolumeId(volumeId))
   if e == nil {
     writeJson(w, r, machine.Server)
   } else {
diff --git a/weed-fs/src/pkg/directory/file_id.go b/weed-fs/src/pkg/directory/file_id.go
index 4d9882897..be5388e61 100644
--- a/weed-fs/src/pkg/directory/file_id.go
+++ b/weed-fs/src/pkg/directory/file_id.go
@@ -4,18 +4,19 @@ import (
 	"encoding/hex"
 	"log"
 	"pkg/storage"
+	"pkg/topology"
 	"strconv"
 	"strings"
 	"pkg/util"
 )
 
 type FileId struct {
-	VolumeId uint32
+	VolumeId topology.VolumeId
 	Key      uint64
 	Hashcode uint32
 }
 
-func NewFileId(VolumeId uint32, Key uint64, Hashcode uint32) *FileId {
+func NewFileId(VolumeId topology.VolumeId, Key uint64, Hashcode uint32) *FileId {
 	return &FileId{VolumeId: VolumeId, Key: Key, Hashcode: Hashcode}
 }
 func ParseFileId(fid string) *FileId{
@@ -27,7 +28,7 @@ func ParseFileId(fid string) *FileId{
 	vid_string, key_hash_string := a[0], a[1]
 	vid, _ := strconv.ParseUint(vid_string, 10, 64)
 	key, hash := storage.ParseKeyHash(key_hash_string)
-	return &FileId{VolumeId: uint32(vid), Key: key, Hashcode: hash}
+	return &FileId{VolumeId: topology.VolumeId(vid), Key: key, Hashcode: hash}
 }
 func (n *FileId) String() string {
 	bytes := make([]byte, 12)
diff --git a/weed-fs/src/pkg/directory/volume_mapping.go b/weed-fs/src/pkg/directory/volume_mapping.go
index 0fb6c6a59..d48a6d12f 100644
--- a/weed-fs/src/pkg/directory/volume_mapping.go
+++ b/weed-fs/src/pkg/directory/volume_mapping.go
@@ -32,8 +32,8 @@ type Mapper struct {
 	volumeLock          sync.Mutex
   sequenceLock          sync.Mutex
 	Machines      []*Machine
-	vid2machineId map[uint32]int //machineId is +1 of the index of []*Machine, to detect not found entries
-	Writers       []uint32       // transient array of Writers volume id
+	vid2machineId map[topology.VolumeId]int //machineId is +1 of the index of []*Machine, to detect not found entries
+	Writers       []topology.VolumeId       // transient array of Writers volume id
 
 	FileIdSequence uint64
 	fileIdCounter  uint64
@@ -47,9 +47,9 @@ func NewMachine(server, publicUrl string, volumes []topology.VolumeInfo) *Machin
 
 func NewMapper(dirname string, filename string, volumeSizeLimit uint64) (m *Mapper) {
 	m = &Mapper{dir: dirname, fileName: filename}
-	m.vid2machineId = make(map[uint32]int)
+	m.vid2machineId = make(map[topology.VolumeId]int)
 	m.volumeSizeLimit = volumeSizeLimit
-	m.Writers = *new([]uint32)
+	m.Writers = *new([]topology.VolumeId)
 	m.Machines = *new([]*Machine)
 
 	seqFile, se := os.OpenFile(path.Join(m.dir, m.fileName+".seq"), os.O_RDONLY, 0644)
@@ -102,7 +102,7 @@ func (m *Mapper) NextFileId(c string) (uint64,int) {
 	m.fileIdCounter = m.fileIdCounter - count
 	return m.FileIdSequence - m.fileIdCounter, int(count)
 }
-func (m *Mapper) Get(vid uint32) (*Machine, error) {
+func (m *Mapper) Get(vid topology.VolumeId) (*Machine, error) {
 	machineId := m.vid2machineId[vid]
 	if machineId <= 0 {
 		return nil, errors.New("invalid volume id " + strconv.FormatUint(uint64(vid), 10))
@@ -134,7 +134,7 @@ func (m *Mapper) Add(machine Machine) {
 		m.vid2machineId[v.Id] = machineId + 1 //use base 1 indexed, to detect not found cases
 	}
 	//setting Writers, copy-on-write because of possible updating, this needs some future work!
-	var writers []uint32
+	var writers []topology.VolumeId
 	for _, machine_entry := range m.Machines {
 		for _, v := range machine_entry.Volumes {
 			if uint64(v.Size) < m.volumeSizeLimit {
diff --git a/weed-fs/src/pkg/storage/store.go b/weed-fs/src/pkg/storage/store.go
index 93907c079..5a686d2db 100644
--- a/weed-fs/src/pkg/storage/store.go
+++ b/weed-fs/src/pkg/storage/store.go
@@ -64,7 +64,7 @@ func (s *Store) Status() *[]*topology.VolumeInfo {
 	stats := new([]*topology.VolumeInfo)
 	for k, v := range s.volumes {
 		s := new(topology.VolumeInfo)
-		s.Id, s.Size = uint32(k), v.Size()
+		s.Id, s.Size = topology.VolumeId(k), v.Size()
 		*stats = append(*stats, s)
 	}
 	return stats
@@ -73,7 +73,7 @@ func (s *Store) Join(mserver string) {
 	stats := new([]*topology.VolumeInfo)
 	for k, v := range s.volumes {
 		s := new(topology.VolumeInfo)
-		s.Id, s.Size = uint32(k), v.Size()
+		s.Id, s.Size = topology.VolumeId(k), v.Size()
 		*stats = append(*stats, s)
 	}
 	bytes, _ := json.Marshal(stats)
diff --git a/weed-fs/src/pkg/topology/node.go b/weed-fs/src/pkg/topology/node.go
index cf48b0d67..2a556e5ad 100644
--- a/weed-fs/src/pkg/topology/node.go
+++ b/weed-fs/src/pkg/topology/node.go
@@ -4,13 +4,15 @@ import (
 
 )
 
+type VolumeId uint32
 type VolumeInfo struct {
-  Id   uint32
+  Id   VolumeId
   Size int64
 }
 type Node struct {
-  volumes     map[uint64]VolumeInfo
+  volumes     map[VolumeId]VolumeInfo
   volumeLimit int
+  Ip          string
   Port        int
   PublicUrl   string
 }