diff --git a/weed-fs/src/cmd/weed/master.go b/weed-fs/src/cmd/weed/master.go
index 13a701e20..a92b7c0f1 100644
--- a/weed-fs/src/cmd/weed/master.go
+++ b/weed-fs/src/cmd/weed/master.go
@@ -41,12 +41,16 @@ func dirLookupHandler(w http.ResponseWriter, r *http.Request) {
 		vid = vid[0:commaSep]
 	}
 	volumeId, _ := storage.NewVolumeId(vid)
-	machine, e := mapper.Get(volumeId)
+	machines, e := mapper.Get(volumeId)
 	if e == nil {
-		writeJson(w, r, map[string]string{"url": machine.Url, "publicUrl": machine.PublicUrl})
+	  var ret []map[string]string
+	  for _, machine := range machines {
+	    ret = append(ret,map[string]string{"url": machine.Url, "publicUrl": machine.PublicUrl})
+	  }
+		writeJson(w, r, ret)
 	} else {
 		log.Println("Invalid volume id", volumeId)
-		writeJson(w, r, map[string]string{"error": "volume id " + volumeId.String() + " not found"})
+		writeJson(w, r, map[string]string{"error": "volume id " + volumeId.String() + " not found. " + e.Error()})
 	}
 }
 func dirAssignHandler(w http.ResponseWriter, r *http.Request) {
diff --git a/weed-fs/src/pkg/directory/volume_mapping.go b/weed-fs/src/pkg/directory/volume_mapping.go
index 6b52268f7..fd1df6e39 100644
--- a/weed-fs/src/pkg/directory/volume_mapping.go
+++ b/weed-fs/src/pkg/directory/volume_mapping.go
@@ -18,10 +18,10 @@ type Machine struct {
 }
 
 type Mapper struct {
-	Machines    map[string]*Machine
-	vid2machine map[storage.VolumeId]*Machine
-	Writers     []storage.VolumeId // transient array of Writers volume id
-	pulse       int64
+	Machines     map[string]*Machine
+	vid2machines map[storage.VolumeId][]*Machine
+	Writers      []storage.VolumeId // transient array of Writers volume id
+	pulse        int64
 
 	volumeSizeLimit uint64
 
@@ -34,7 +34,7 @@ func NewMachine(server, publicUrl string, volumes []storage.VolumeInfo, lastSeen
 
 func NewMapper(dirname string, filename string, volumeSizeLimit uint64, pulse int) (m *Mapper) {
 	m = &Mapper{}
-	m.vid2machine = make(map[storage.VolumeId]*Machine)
+	m.vid2machines = make(map[storage.VolumeId][]*Machine)
 	m.volumeSizeLimit = volumeSizeLimit
 	m.Writers = *new([]storage.VolumeId)
 	m.Machines = make(map[string]*Machine)
@@ -51,37 +51,65 @@ func (m *Mapper) PickForWrite(c string) (string, int, *Machine, error) {
 		return "", 0, nil, errors.New("No more writable volumes!")
 	}
 	vid := m.Writers[rand.Intn(len_writers)]
-	machine := m.vid2machine[vid]
-	if machine != nil {
+	machines := m.vid2machines[vid]
+	if machines != nil && len(machines)>0 {
 		fileId, count := m.sequence.NextFileId(util.ParseInt(c, 1))
 		if count == 0 {
 			return "", 0, nil, errors.New("Strange count:" + c)
 		}
-		return NewFileId(vid, fileId, rand.Uint32()).String(), count, machine, nil
+		//always use the first server to write
+		return NewFileId(vid, fileId, rand.Uint32()).String(), count, machines[0], nil
 	}
 	return "", 0, nil, errors.New("Strangely vid " + vid.String() + " is on no machine!")
 }
-func (m *Mapper) Get(vid storage.VolumeId) (*Machine, error) {
-	machine := m.vid2machine[vid]
-	if machine == nil {
+func (m *Mapper) Get(vid storage.VolumeId) ([]*Machine, error) {
+	machines := m.vid2machines[vid]
+	if machines == nil {
 		return nil, errors.New("invalid volume id " + vid.String())
 	}
-	return machine, nil
+	return machines, nil
 }
 func (m *Mapper) Add(machine *Machine) {
 	m.Machines[machine.Url] = machine
 	//add to vid2machine map, and Writers array
 	for _, v := range machine.Volumes {
-		m.vid2machine[v.Id] = machine
+		list := m.vid2machines[v.Id]
+		found := false
+		for index, entry := range list {
+			if machine.Url == entry.Url {
+				list[index] = machine
+				found = true
+			}
+		}
+		if !found {
+			m.vid2machines[v.Id] = append(m.vid2machines[v.Id], machine)
+		}
 	}
 	m.refreshWritableVolumes()
 }
 func (m *Mapper) remove(machine *Machine) {
-  delete(m.Machines,machine.Url)
-  for _, v := range machine.Volumes {
-    delete(m.vid2machine,v.Id)
-  }
+	delete(m.Machines, machine.Url)
+	for _, v := range machine.Volumes {
+    list := m.vid2machines[v.Id]
+    foundIndex := -1
+    for index, entry := range list {
+      if machine.Url == entry.Url {
+        foundIndex = index
+      }
+    }
+    m.vid2machines[v.Id] = deleteFromSlice(foundIndex,m.vid2machines[v.Id])
+	}
 }
+func deleteFromSlice(i int, slice []*Machine) []*Machine{
+    switch i {
+        case -1://do nothing
+        case 0: slice = slice[1:]
+        case len(slice)-1: slice = slice[:len(slice)-1]
+        default: slice = append(slice[:i], slice[i+1:]...)
+    }
+    return slice
+}
+
 func (m *Mapper) StartRefreshWritableVolumes() {
 	go func() {
 		for {