diff --git a/weed/server/master_server_handlers_admin.go b/weed/server/master_server_handlers_admin.go
index 67c030042..88c7f1d34 100644
--- a/weed/server/master_server_handlers_admin.go
+++ b/weed/server/master_server_handlers_admin.go
@@ -11,7 +11,7 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/operation"
 	"github.com/chrislusf/seaweedfs/weed/pb/volume_server_pb"
 	"github.com/chrislusf/seaweedfs/weed/storage"
-	"github.com/chrislusf/seaweedfs/weed/storage/memory_map"
+	"github.com/chrislusf/seaweedfs/weed/storage/backend/memory_map"
 	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 	"github.com/chrislusf/seaweedfs/weed/topology"
 	"github.com/chrislusf/seaweedfs/weed/util"
diff --git a/weed/storage/memory_map/memory_map.go b/weed/storage/backend/memory_map/memory_map.go
similarity index 100%
rename from weed/storage/memory_map/memory_map.go
rename to weed/storage/backend/memory_map/memory_map.go
diff --git a/weed/storage/memory_map/memory_map_other.go b/weed/storage/backend/memory_map/memory_map_other.go
similarity index 100%
rename from weed/storage/memory_map/memory_map_other.go
rename to weed/storage/backend/memory_map/memory_map_other.go
diff --git a/weed/storage/memory_map/memory_map_test.go b/weed/storage/backend/memory_map/memory_map_test.go
similarity index 100%
rename from weed/storage/memory_map/memory_map_test.go
rename to weed/storage/backend/memory_map/memory_map_test.go
diff --git a/weed/storage/memory_map/memory_map_windows.go b/weed/storage/backend/memory_map/memory_map_windows.go
similarity index 100%
rename from weed/storage/memory_map/memory_map_windows.go
rename to weed/storage/backend/memory_map/memory_map_windows.go
diff --git a/weed/storage/memory_map/os_overloads/file_windows.go b/weed/storage/backend/memory_map/os_overloads/file_windows.go
similarity index 100%
rename from weed/storage/memory_map/os_overloads/file_windows.go
rename to weed/storage/backend/memory_map/os_overloads/file_windows.go
diff --git a/weed/storage/memory_map/os_overloads/syscall_windows.go b/weed/storage/backend/memory_map/os_overloads/syscall_windows.go
similarity index 100%
rename from weed/storage/memory_map/os_overloads/syscall_windows.go
rename to weed/storage/backend/memory_map/os_overloads/syscall_windows.go
diff --git a/weed/storage/memory_map/os_overloads/types_windows.go b/weed/storage/backend/memory_map/os_overloads/types_windows.go
similarity index 100%
rename from weed/storage/memory_map/os_overloads/types_windows.go
rename to weed/storage/backend/memory_map/os_overloads/types_windows.go
diff --git a/weed/storage/needle/needle_read_write.go b/weed/storage/needle/needle_read_write.go
index 5f8bfee8b..42736bda1 100644
--- a/weed/storage/needle/needle_read_write.go
+++ b/weed/storage/needle/needle_read_write.go
@@ -9,7 +9,7 @@ import (
 	"math"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
-	"github.com/chrislusf/seaweedfs/weed/storage/memory_map"
+	"github.com/chrislusf/seaweedfs/weed/storage/backend/memory_map"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 	"github.com/chrislusf/seaweedfs/weed/util"
 )
diff --git a/weed/storage/volume_create_windows.go b/weed/storage/volume_create_windows.go
index db0734436..12826f613 100644
--- a/weed/storage/volume_create_windows.go
+++ b/weed/storage/volume_create_windows.go
@@ -5,11 +5,11 @@ package storage
 import (
 	"os"
 
-	"github.com/chrislusf/seaweedfs/weed/storage/memory_map"
+	"github.com/chrislusf/seaweedfs/weed/storage/backend/memory_map"
 	"golang.org/x/sys/windows"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
-	"github.com/chrislusf/seaweedfs/weed/storage/memory_map/os_overloads"
+	"github.com/chrislusf/seaweedfs/weed/storage/backend/memory_map/os_overloads"
 )
 
 func createVolumeFile(fileName string, preallocate int64, memoryMapSizeMB uint32) (*os.File, error) {
diff --git a/weed/storage/volume_read_write.go b/weed/storage/volume_read_write.go
index 5f18dc042..7c9539021 100644
--- a/weed/storage/volume_read_write.go
+++ b/weed/storage/volume_read_write.go
@@ -9,7 +9,7 @@ import (
 	"time"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
-	"github.com/chrislusf/seaweedfs/weed/storage/memory_map"
+	"github.com/chrislusf/seaweedfs/weed/storage/backend/memory_map"
 	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 	. "github.com/chrislusf/seaweedfs/weed/storage/types"
 )
diff --git a/weed/storage/volume_super_block.go b/weed/storage/volume_super_block.go
index e05f5ee48..2c2553666 100644
--- a/weed/storage/volume_super_block.go
+++ b/weed/storage/volume_super_block.go
@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"os"
 
-	"github.com/chrislusf/seaweedfs/weed/storage/memory_map"
+	"github.com/chrislusf/seaweedfs/weed/storage/backend/memory_map"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"