diff --git a/weed/storage/volume_create.go b/weed/storage/volume_create.go
index ffcb246a4..422537a24 100644
--- a/weed/storage/volume_create.go
+++ b/weed/storage/volume_create.go
@@ -9,7 +9,7 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/storage/backend"
 )
 
-func createVolumeFile(fileName string, preallocate int64, memoryMapSizeMB uint32) (backend.BackendStorageFile, error) {
+func CreateVolumeFile(fileName string, preallocate int64, memoryMapSizeMB uint32) (backend.BackendStorageFile, error) {
 	file, e := os.OpenFile(fileName, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
 	if e != nil {
 		return nil, e
diff --git a/weed/storage/volume_create_linux.go b/weed/storage/volume_create_linux.go
index ee599ac32..a854c531a 100644
--- a/weed/storage/volume_create_linux.go
+++ b/weed/storage/volume_create_linux.go
@@ -10,7 +10,7 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/storage/backend"
 )
 
-func createVolumeFile(fileName string, preallocate int64, memoryMapSizeMB uint32) (backend.BackendStorageFile, error) {
+func CreateVolumeFile(fileName string, preallocate int64, memoryMapSizeMB uint32) (backend.BackendStorageFile, error) {
 	file, e := os.OpenFile(fileName, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
 	if e != nil {
 		return nil, e
diff --git a/weed/storage/volume_create_windows.go b/weed/storage/volume_create_windows.go
index e1c0b961f..e347cbd1c 100644
--- a/weed/storage/volume_create_windows.go
+++ b/weed/storage/volume_create_windows.go
@@ -11,7 +11,7 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/storage/backend/memory_map/os_overloads"
 )
 
-func createVolumeFile(fileName string, preallocate int64, memoryMapSizeMB uint32) (backend.BackendStorageFile, error) {
+func CreateVolumeFile(fileName string, preallocate int64, memoryMapSizeMB uint32) (backend.BackendStorageFile, error) {
 	if preallocate > 0 {
 		glog.V(0).Infof("Preallocated disk space for %s is not supported", fileName)
 	}
diff --git a/weed/storage/volume_loading.go b/weed/storage/volume_loading.go
index 3b0897bca..64979cba1 100644
--- a/weed/storage/volume_loading.go
+++ b/weed/storage/volume_loading.go
@@ -54,7 +54,7 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 		v.DataBackend = backend.NewDiskFile(dataFile)
 	} else {
 		if createDatIfMissing {
-			v.DataBackend, err = createVolumeFile(fileName+".dat", preallocate, v.MemoryMapMaxSizeMb)
+			v.DataBackend, err = CreateVolumeFile(fileName+".dat", preallocate, v.MemoryMapMaxSizeMb)
 		} else {
 			return fmt.Errorf("Volume Data file %s.dat does not exist.", fileName)
 		}
diff --git a/weed/storage/volume_vacuum.go b/weed/storage/volume_vacuum.go
index 67c3957de..ce3ab3a46 100644
--- a/weed/storage/volume_vacuum.go
+++ b/weed/storage/volume_vacuum.go
@@ -354,7 +354,7 @@ func (v *Volume) copyDataAndGenerateIndexFile(dstName, idxName string, prealloca
 	var (
 		dst backend.BackendStorageFile
 	)
-	if dst, err = createVolumeFile(dstName, preallocate, 0); err != nil {
+	if dst, err = CreateVolumeFile(dstName, preallocate, 0); err != nil {
 		return
 	}
 	defer dst.Close()
@@ -383,7 +383,7 @@ func copyDataBasedOnIndexFile(srcDatName, srcIdxName, dstDatName, datIdxName str
 		srcDatBackend, dstDatBackend backend.BackendStorageFile
 		dataFile                     *os.File
 	)
-	if dstDatBackend, err = createVolumeFile(dstDatName, preallocate, 0); err != nil {
+	if dstDatBackend, err = CreateVolumeFile(dstDatName, preallocate, 0); err != nil {
 		return
 	}
 	defer dstDatBackend.Close()