diff --git a/weed/storage/needle_map.go b/weed/storage/needle_map.go
index f2ff9bb76..9aa8fa561 100644
--- a/weed/storage/needle_map.go
+++ b/weed/storage/needle_map.go
@@ -2,7 +2,6 @@ package storage
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"sync"
 
@@ -31,8 +30,6 @@ type NeedleMapper interface {
 	DeletedCount() int
 	MaxFileKey() NeedleId
 	IndexFileSize() uint64
-	IndexFileContent() ([]byte, error)
-	IndexFileName() string
 }
 
 type baseNeedleMapper struct {
@@ -50,10 +47,6 @@ func (nm *baseNeedleMapper) IndexFileSize() uint64 {
 	return 0
 }
 
-func (nm *baseNeedleMapper) IndexFileName() string {
-	return nm.indexFile.Name()
-}
-
 func (nm *baseNeedleMapper) appendToIndexFile(key NeedleId, offset Offset, size uint32) error {
 	bytes := needle_map.ToBytes(key, offset, size)
 
@@ -66,9 +59,3 @@ func (nm *baseNeedleMapper) appendToIndexFile(key NeedleId, offset Offset, size
 	_, err := nm.indexFile.Write(bytes)
 	return err
 }
-
-func (nm *baseNeedleMapper) IndexFileContent() ([]byte, error) {
-	nm.indexFileAccessLock.Lock()
-	defer nm.indexFileAccessLock.Unlock()
-	return ioutil.ReadFile(nm.indexFile.Name())
-}
diff --git a/weed/storage/volume.go b/weed/storage/volume.go
index afe3b4c8a..92839f9e6 100644
--- a/weed/storage/volume.go
+++ b/weed/storage/volume.go
@@ -90,51 +90,57 @@ func (v *Volume) FileStat() (datSize uint64, idxSize uint64, modTime time.Time)
 func (v *Volume) ContentSize() uint64 {
 	v.dataFileAccessLock.Lock()
 	defer v.dataFileAccessLock.Unlock()
+	if v.nm == nil {
+		return 0
+	}
 	return v.nm.ContentSize()
 }
 
 func (v *Volume) DeletedSize() uint64 {
 	v.dataFileAccessLock.Lock()
 	defer v.dataFileAccessLock.Unlock()
+	if v.nm == nil {
+		return 0
+	}
 	return v.nm.DeletedSize()
 }
 
 func (v *Volume) FileCount() uint64 {
 	v.dataFileAccessLock.Lock()
 	defer v.dataFileAccessLock.Unlock()
+	if v.nm == nil {
+		return 0
+	}
 	return uint64(v.nm.FileCount())
 }
 
 func (v *Volume) DeletedCount() uint64 {
 	v.dataFileAccessLock.Lock()
 	defer v.dataFileAccessLock.Unlock()
+	if v.nm == nil {
+		return 0
+	}
 	return uint64(v.nm.DeletedCount())
 }
 
 func (v *Volume) MaxFileKey() types.NeedleId {
 	v.dataFileAccessLock.Lock()
 	defer v.dataFileAccessLock.Unlock()
+	if v.nm == nil {
+		return 0
+	}
 	return v.nm.MaxFileKey()
 }
 
 func (v *Volume) IndexFileSize() uint64 {
 	v.dataFileAccessLock.Lock()
 	defer v.dataFileAccessLock.Unlock()
+	if v.nm == nil {
+		return 0
+	}
 	return v.nm.IndexFileSize()
 }
 
-func (v *Volume) IndexFileContent() ([]byte, error) {
-	v.dataFileAccessLock.Lock()
-	defer v.dataFileAccessLock.Unlock()
-	return v.nm.IndexFileContent()
-}
-
-func (v *Volume) IndexFileName() string {
-	v.dataFileAccessLock.Lock()
-	defer v.dataFileAccessLock.Unlock()
-	return v.nm.IndexFileName()
-}
-
 // Close cleanly shuts down this volume
 func (v *Volume) Close() {
 	v.dataFileAccessLock.Lock()