diff --git a/weed-fs/note/weedfs.txt b/weed-fs/note/weedfs.txt
new file mode 100644
index 000000000..d07ad9484
--- /dev/null
+++ b/weed-fs/note/weedfs.txt
@@ -0,0 +1,46 @@
+How to submit a content
+1. Find physical volumes
+1.c Create a hash value
+1.d find a write logic volume id, and return [logic volume id, {physical volume ids}]
+2. submit to physical volumes
+2.c 
+  generate the cookie
+  generate a unique id as key
+  choose the right altKey
+  send bytes to physical volumes
+2.s each
+  save bytes
+  store map[key uint64, altKey uint32]<offset, size>
+    for updated entry, set old entry's offset to zero
+3.c
+  wait for all physical volumes to finish
+  store the /<logic volume id>/<key>_<cookie>_<altKey>.<ext>
+
+How to retrieve a content
+1.c
+  send logic volume id
+1.d
+  find least busy volume's id
+2.c
+  send URI /<physical volume id>/<key>_<cookie>_<altKey>.<ext>
+
+
+How to submit a content
+1. send bytes to weedfs, got <volume id, key uint64, cookie code>
+   store <key uint64, volume id uint32, cookie code uint32, ext>, and other information
+
+To read a content
+2. use logic volume id to lookup a <machine id>
+   render url as /<machine id>/<volume id>/<key>/<cookie>.ext
+
+The directory server
+0.init
+  load and collect <logic volume id, machine ids> mapping
+1.on submit content
+  find a free logic volume id, start sending content to 3 machines
+  if all of them finishes, return <logic volume id, key, cookie code>
+2.on read content
+  based on logic volume id, pick a machine with less load, 
+    return <machine id>
+  
+
diff --git a/weed-fs/src/cmd/gdir.go b/weed-fs/src/cmd/gdir.go
deleted file mode 100644
index 34c5733be..000000000
--- a/weed-fs/src/cmd/gdir.go
+++ /dev/null
@@ -1,18 +0,0 @@
-package main
-
-import (
-	"directory"
-	//    "runtime"
-	"log"
-)
-
-func main() {
-	m := directory.NewMapper("/tmp", "directory")
-	log.Println("map size", len(m.Virtual2physical))
-	m.Add(10, 11,12,13)
-	m.Add(20, 21,22,23)
-    log.Println("map(10)", m.Get(10))
-    log.Println("map size", len(m.Virtual2physical))
-	m.Save()
-	defer m.Save()
-}
diff --git a/weed-fs/src/cmd/gstore.go b/weed-fs/src/cmd/gstore.go
index 8bd240902..a86e30373 100644
--- a/weed-fs/src/cmd/gstore.go
+++ b/weed-fs/src/cmd/gstore.go
@@ -6,9 +6,11 @@ import (
 	"flag"
 	"fmt"
 	"http"
+	"json"
 	"log"
 	"mime"
 	"os"
+	"rand"
 	"strconv"
 	"strings"
 )
@@ -18,6 +20,10 @@ var (
 	chunkFolder  = flag.String("dir", "/tmp", "data directory to store files")
 	chunkCount   = flag.Int("chunks", 5, "data chunks to store files")
 	chunkEnabled = flag.Bool("data", false, "act as a store server")
+    chunkServer   = flag.String("cserver", "localhost:8080", "chunk server to store data")
+    publicServer   = flag.String("pserver", "localhost:8080", "public server to serve data read")
+    metaServer   = flag.String("mserver", "localhost:8080", "metadata server to store mappings")
+
 	metaEnabled  = flag.Bool("meta", false, "act as a directory server")
 	metaFolder   = flag.String("mdir", "/tmp", "data directory to store mappings")
 )
@@ -41,7 +47,7 @@ func (s *Haystack) GetHandler(w http.ResponseWriter, r *http.Request) {
 	n := new(store.Needle)
 	path := r.URL.Path
 	sepIndex := strings.Index(path[1:], "/") + 1
-	volumeId, _ := strconv.Atoi(path[1:sepIndex])
+	volumeId, _ := strconv.Atoui64(path[1:sepIndex])
 	dotIndex := strings.LastIndex(path, ".")
 	n.ParsePath(path[sepIndex+1 : dotIndex])
 	ext := path[dotIndex:]
@@ -51,14 +57,47 @@ func (s *Haystack) GetHandler(w http.ResponseWriter, r *http.Request) {
 	w.Write(n.Data)
 }
 func (s *Haystack) PostHandler(w http.ResponseWriter, r *http.Request) {
-	volumeId := s.store.Write(store.NewNeedle(r))
+    volumeId, _ := strconv.Atoui64(r.FormValue("volumeId"))
+	s.store.Write(volumeId, store.NewNeedle(r))
 	w.Header().Set("Content-Type", "text/plain")
 	fmt.Fprint(w, "volumeId=", volumeId, "\n")
 }
 func (s *Haystack) DeleteHandler(w http.ResponseWriter, r *http.Request) {
 
 }
-func directoryHandler(w http.ResponseWriter, r *http.Request) {
+func dirReadHandler(w http.ResponseWriter, r *http.Request) {
+    volumeId, _ := strconv.Atoui64(r.FormValue("volumeId"))
+    machineList := server.directory.Get((uint32)(volumeId))
+    x := rand.Intn(len(machineList))
+    machine := machineList[x]
+    bytes, _ := json.Marshal(machine)
+    callback := r.FormValue("callback")
+    w.Header().Set("Content-Type", "application/javascript")
+    if callback == "" {
+        w.Write(bytes)
+    } else {
+        w.Write([]uint8(callback))
+        w.Write([]uint8("("))
+        w.Write(bytes)
+        w.Write([]uint8(")"))
+    }
+}
+func dirWriteHandler(w http.ResponseWriter, r *http.Request) {
+    machineList := server.directory.PickForWrite()
+    bytes, _ := json.Marshal(machineList)
+    callback := r.FormValue("callback")
+    w.Header().Set("Content-Type", "application/javascript")
+    if callback == "" {
+        w.Write(bytes)
+    } else {
+        w.Write([]uint8(callback))
+        w.Write([]uint8("("))
+        w.Write(bytes)
+        w.Write([]uint8(")"))
+    }
+}
+func dirJoinHandler(w http.ResponseWriter, r *http.Request) {
+
 }
 
 var server *Haystack
@@ -66,22 +105,24 @@ var server *Haystack
 func main() {
 	flag.Parse()
 	if !*chunkEnabled && !*metaEnabled {
-		fmt.Fprintf(os.Stderr, "Need to act as either a store server or a directory server, or both\n")
-		flag.PrintDefaults()
-		os.Exit(-1)
+		fmt.Fprintf(os.Stdout, "Act as both a store server and a directory server\n")
 	}
 	server = new(Haystack)
 	if *chunkEnabled {
 		fmt.Fprintf(os.Stdout, "Chunk data stored in %s\n", *chunkFolder)
-		server.store = store.NewStore(*chunkFolder, *chunkCount)
+		server.store = store.NewStore(*chunkServer, *publicServer, *chunkFolder)
 		defer server.store.Close()
 		http.HandleFunc("/", storeHandler)
 	}
 	if *metaEnabled {
 		server.directory = directory.NewMapper(*metaFolder, "directory")
 		defer server.directory.Save()
-        http.HandleFunc("/directory", directoryHandler)
+        http.HandleFunc("/dir/read", dirReadHandler)
+        http.HandleFunc("/dir/write", dirWriteHandler)
+        http.HandleFunc("/dir/join", dirJoinHandler)
 	}
+	
+	server.store.Join(*metaServer)
 
 	log.Println("Serving at http://127.0.0.1:" + strconv.Itoa(*port))
 	http.ListenAndServe(":"+strconv.Itoa(*port), nil)
diff --git a/weed-fs/src/pkg/directory/volume_mapping.go b/weed-fs/src/pkg/directory/volume_mapping.go
index 60fef7d7d..963145153 100644
--- a/weed-fs/src/pkg/directory/volume_mapping.go
+++ b/weed-fs/src/pkg/directory/volume_mapping.go
@@ -3,13 +3,17 @@ package directory
 import (
 	"gob"
 	"os"
+	"rand"
 	"log"
 )
 
+type Machine struct {
+    Server           string //<server name/ip>[:port]
+}
 type Mapper struct {
 	dir              string
 	fileName         string
-	Virtual2physical map[uint32][]uint32
+	Virtual2physical map[uint32][]Machine
 }
 
 func NewMapper(dirname string, filename string) (m *Mapper) {
@@ -21,17 +25,21 @@ func NewMapper(dirname string, filename string) (m *Mapper) {
 	if e != nil {
 		log.Fatalf("Mapping File Read [ERROR] %s\n", e)
 	} else {
-		m.Virtual2physical = make(map[uint32][]uint32)
+		m.Virtual2physical = make(map[uint32][]Machine)
 		decoder := gob.NewDecoder(dataFile)
 		decoder.Decode(m.Virtual2physical)
         dataFile.Close()
 	}
 	return
 }
-func (m *Mapper) Get(vid uint32) []uint32 {
+func (m *Mapper) PickForWrite() []Machine {
+    vid := uint32(rand.Intn(len(m.Virtual2physical)))
+    return m.Virtual2physical[vid]
+}
+func (m *Mapper) Get(vid uint32) []Machine {
 	return m.Virtual2physical[vid]
 }
-func (m *Mapper) Add(vid uint32, pids ...uint32) {
+func (m *Mapper) Add(vid uint32, pids ...Machine) {
 	m.Virtual2physical[vid] = append(m.Virtual2physical[vid], pids...)
 }
 func (m *Mapper) Save() {
@@ -41,7 +49,7 @@ func (m *Mapper) Save() {
 		log.Fatalf("Mapping File Save [ERROR] %s\n", e)
 	}
 	defer dataFile.Close()
-	m.Virtual2physical = make(map[uint32][]uint32)
+	m.Virtual2physical = make(map[uint32][]Machine)
 	encoder := gob.NewEncoder(dataFile)
 	encoder.Encode(m.Virtual2physical)
 }
diff --git a/weed-fs/src/pkg/store/store.go b/weed-fs/src/pkg/store/store.go
index a568fb199..c287aaaa8 100644
--- a/weed-fs/src/pkg/store/store.go
+++ b/weed-fs/src/pkg/store/store.go
@@ -1,39 +1,69 @@
 package store
 
 import (
-    "log"
-    "strconv"
+	"log"
+	"io/ioutil"
+	"json"
+	"strings"
+	"strconv"
+	"url"
 )
-type Store struct{
-  volumes []*Volume
-  dir string
-  
-  freeVolumeChannel chan int
+
+type Store struct {
+	volumes      map[uint64]*Volume
+	dir          string
+	Server       string
+	PublicServer string
+}
+type VolumeStat struct {
+	Id     uint64 "id"
+	Status int    "status" //0:read, 1:write
+}
+
+func NewStore(server, publicServer, dirname string) (s *Store) {
+	s = new(Store)
+	s.Server, s.PublicServer, s.dir = server, publicServer, dirname
+	s.volumes = make(map[uint64]*Volume)
+
+	counter := uint64(0)
+	files, _ := ioutil.ReadDir(dirname)
+	for _, f := range files {
+		if f.IsDirectory() || !strings.HasSuffix(f.Name, ".dat") {
+			continue
+		}
+		id, err := strconv.Atoui64(f.Name[:-4])
+		if err == nil {
+			continue
+		}
+		s.volumes[counter] = NewVolume(s.dir, id)
+		counter++
+	}
+	log.Println("Store started on dir:", dirname, "with", counter, "existing volumes")
+	return
 }
-func NewStore(dirname string, count int) (s *Store){
-  s = new(Store)
-  s.dir = dirname
-  s.volumes = make([]*Volume,count)
-  s.freeVolumeChannel = make(chan int, count)
-  for i:=0;i<count;i++{
-    s.volumes[i] = NewVolume(s.dir, strconv.Itob(i,16))
-    s.freeVolumeChannel <- i
-  }
-  log.Println("Store started on dir:", dirname, "with", count,"volumes");
-  return
+
+func (s *Store) Join(mserver string) {
+	stats := make([]*VolumeStat, len(s.volumes))
+	for k, _ := range s.volumes {
+		s := new(VolumeStat)
+		s.Id, s.Status = k, 1
+		stats = append(stats, s)
+	}
+	bytes, _ := json.Marshal(stats)
+	values := new(url.Values)
+	values.Add("server", s.Server)
+    values.Add("publicServer", s.PublicServer)
+	values.Add("volumes", string(bytes))
+	post("http://"+mserver+"/join", *values)
 }
-func (s *Store)Close(){
-  close(s.freeVolumeChannel)
-  for _, v := range s.volumes{
-    v.Close()
-  }
+func (s *Store) Close() {
+	for _, v := range s.volumes {
+		v.Close()
+	}
 }
-func (s *Store)Write(n *Needle)(int){
-  i := <- s.freeVolumeChannel
-  s.volumes[i].write(n)
-  s.freeVolumeChannel <- i
-  return i
+func (s *Store) Write(i uint64, n *Needle) {
+	s.volumes[i].write(n)
 }
-func (s *Store)Read(i int, n *Needle){
-  s.volumes[i].read(n)
+func (s *Store) Read(i uint64, n *Needle) {
+	s.volumes[i].read(n)
 }
diff --git a/weed-fs/src/pkg/store/util.go b/weed-fs/src/pkg/store/util.go
index 258dec482..41b129683 100644
--- a/weed-fs/src/pkg/store/util.go
+++ b/weed-fs/src/pkg/store/util.go
@@ -1,5 +1,12 @@
 package store
 
+import (
+    "http"
+    "io/ioutil"
+    "url"
+    "log"
+)
+
 func bytesToUint64(b []byte)(v uint64){
   for i :=uint(7);i>0;i-- {
     v += uint64(b[i])
@@ -26,3 +33,18 @@ func uint32toBytes(b []byte, v uint32){
     b[i] = byte(v>>(i*8))
   }
 }
+
+func post(url string, values url.Values)string{
+    r, err := http.PostForm(url, values)
+    if err != nil {
+        log.Println("post:", err)
+        return ""
+    }
+    defer r.Body.Close()
+    b, err := ioutil.ReadAll(r.Body)
+    if err != nil {
+        log.Println("post:", err)
+        return ""
+    }
+    return string(b)
+}
\ No newline at end of file
diff --git a/weed-fs/src/pkg/store/volume.go b/weed-fs/src/pkg/store/volume.go
index 33b010e62..c32f4af10 100644
--- a/weed-fs/src/pkg/store/volume.go
+++ b/weed-fs/src/pkg/store/volume.go
@@ -2,29 +2,32 @@ package store
 
 import (
 	"os"
+	"path"
+	"strconv"
 	"log"
 )
 
 type Volume struct {
+	Id                  uint64
 	dir                 string
-	fileName            string
 	dataFile, indexFile *os.File
 	nm                  *NeedleMap
 
 	accessChannel chan int
 }
 
-func NewVolume(dirname string, filename string) (v *Volume) {
+func NewVolume(dirname string, id uint64) (v *Volume) {
 	var e os.Error
 	v = new(Volume)
 	v.dir = dirname
-	v.fileName = filename
-	log.Println("file", v.dir, "/", v.fileName)
-	v.dataFile, e = os.OpenFile(v.dir+string(os.PathSeparator)+v.fileName+".dat", os.O_RDWR|os.O_CREATE, 0644)
+	v.Id = id
+	fileName := strconv.Uitoa64(v.Id)
+	log.Println("file", v.dir, "/", fileName)
+	v.dataFile, e = os.OpenFile(path.Join(v.dir,fileName+".dat"), os.O_RDWR|os.O_CREATE, 0644)
 	if e != nil {
 		log.Fatalf("New Volume [ERROR] %s\n", e)
 	}
-	v.indexFile, e = os.OpenFile(v.dir+string(os.PathSeparator)+v.fileName+".idx", os.O_RDWR|os.O_CREATE, 0644)
+	v.indexFile, e = os.OpenFile(path.Join(v.dir,fileName+".idx"), os.O_RDWR|os.O_CREATE, 0644)
 	if e != nil {
 		log.Fatalf("New Volume [ERROR] %s\n", e)
 	}