diff --git a/weed-fs/src/cmd/weed/master.go b/weed-fs/src/cmd/weed/master.go
index 37d3b2295..ef416a83c 100644
--- a/weed-fs/src/cmd/weed/master.go
+++ b/weed-fs/src/cmd/weed/master.go
@@ -38,13 +38,13 @@ func dirLookupHandler(w http.ResponseWriter, r *http.Request) {
   if commaSep > 0 {
     vid = vid[0:commaSep]
   }
-  volumeId, _ := strconv.ParseUint(vid, 10, 64)
-  machine, e := mapper.Get(storage.VolumeId(volumeId))
+  volumeId, _ := storage.NewVolumeId(vid)
+  machine, e := mapper.Get(volumeId)
   if e == nil {
     writeJson(w, r, machine.Server)
   } else {
     log.Println("Invalid volume id", volumeId)
-    writeJson(w, r, map[string]string{"error": "volume id " + strconv.FormatUint(volumeId, 10) + " not found"})
+    writeJson(w, r, map[string]string{"error": "volume id " + volumeId.String() + " not found"})
   }
 }
 func dirAssignHandler(w http.ResponseWriter, r *http.Request) {
diff --git a/weed-fs/src/pkg/directory/file_id.go b/weed-fs/src/pkg/directory/file_id.go
index 723d94276..62fc354bf 100644
--- a/weed-fs/src/pkg/directory/file_id.go
+++ b/weed-fs/src/pkg/directory/file_id.go
@@ -4,7 +4,6 @@ import (
 	"encoding/hex"
 	"log"
 	"pkg/storage"
-	"strconv"
 	"strings"
 	"pkg/util"
 )
@@ -25,9 +24,9 @@ func ParseFileId(fid string) *FileId{
 		return nil
 	}
 	vid_string, key_hash_string := a[0], a[1]
-	vid, _ := strconv.ParseUint(vid_string, 10, 64)
+  volumeId, _ := storage.NewVolumeId(vid_string)
 	key, hash := storage.ParseKeyHash(key_hash_string)
-	return &FileId{VolumeId: storage.VolumeId(vid), Key: key, Hashcode: hash}
+	return &FileId{VolumeId: volumeId, Key: key, Hashcode: hash}
 }
 func (n *FileId) String() string {
 	bytes := make([]byte, 12)
@@ -36,5 +35,5 @@ func (n *FileId) String() string {
 	nonzero_index := 0
 	for ; bytes[nonzero_index] == 0; nonzero_index++ {
 	}
-	return strconv.FormatUint(uint64(n.VolumeId), 10) + "," + hex.EncodeToString(bytes[nonzero_index:])
+	return n.VolumeId.String() + "," + hex.EncodeToString(bytes[nonzero_index:])
 }
diff --git a/weed-fs/src/pkg/directory/volume_mapping.go b/weed-fs/src/pkg/directory/volume_mapping.go
index a6748f5c6..445179bc3 100644
--- a/weed-fs/src/pkg/directory/volume_mapping.go
+++ b/weed-fs/src/pkg/directory/volume_mapping.go
@@ -82,7 +82,7 @@ func (m *Mapper) PickForWrite(c string) (string, int, MachineInfo, error) {
 		}
 		return NewFileId(vid, fileId, rand.Uint32()).String(), count, machine.Server, nil
 	}
-	return "", 0, m.Machines[rand.Intn(len(m.Machines))].Server, errors.New("Strangely vid " + strconv.FormatUint(uint64(vid), 10) + " is on no machine!")
+	return "", 0, m.Machines[rand.Intn(len(m.Machines))].Server, errors.New("Strangely vid " + vid.String() + " is on no machine!")
 }
 func (m *Mapper) NextFileId(c string) (uint64,int) {
   count, parseError := strconv.ParseUint(c,10,64)
@@ -105,7 +105,7 @@ func (m *Mapper) NextFileId(c string) (uint64,int) {
 func (m *Mapper) Get(vid storage.VolumeId) (*Machine, error) {
 	machineId := m.vid2machineId[vid]
 	if machineId <= 0 {
-		return nil, errors.New("invalid volume id " + strconv.FormatUint(uint64(vid), 10))
+		return nil, errors.New("invalid volume id " + vid.String())
 	}
 	return m.Machines[machineId-1], nil
 }
diff --git a/weed-fs/src/pkg/storage/volume.go b/weed-fs/src/pkg/storage/volume.go
index 2f156a13b..519ebab4d 100644
--- a/weed-fs/src/pkg/storage/volume.go
+++ b/weed-fs/src/pkg/storage/volume.go
@@ -37,7 +37,7 @@ type Volume struct {
 func NewVolume(dirname string, id VolumeId) (v *Volume) {
 	var e error
 	v = &Volume{dir: dirname, Id: id}
-	fileName := strconv.FormatUint(uint64(v.Id), 10)
+	fileName := id.String()
 	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)