diff --git a/weed/filer2/filechunks.go b/weed/filer2/filechunks.go
new file mode 100644
index 000000000..b2f05de3a
--- /dev/null
+++ b/weed/filer2/filechunks.go
@@ -0,0 +1,23 @@
+package filer2
+
+type Chunks []FileChunk
+
+func (chunks Chunks) TotalSize() (size uint64) {
+	for _, c := range chunks {
+		t := uint64(c.Offset + int64(c.Size))
+		if size < t {
+			size = t
+		}
+	}
+	return
+}
+
+func (chunks Chunks) Len() int {
+	return len(chunks)
+}
+func (chunks Chunks) Swap(i, j int) {
+	chunks[i], chunks[j] = chunks[j], chunks[i]
+}
+func (chunks Chunks) Less(i, j int) bool {
+	return chunks[i].Offset < chunks[j].Offset
+}
diff --git a/weed/filer2/filer_structure.go b/weed/filer2/filer_structure.go
index c78704184..c6a3f817d 100644
--- a/weed/filer2/filer_structure.go
+++ b/weed/filer2/filer_structure.go
@@ -27,7 +27,6 @@ type Attr struct {
 	Mode   os.FileMode // file mode
 	Uid    uint32      // owner uid
 	Gid    uint32      // group gid
-	Size   uint64      // total size in bytes
 }
 
 type Entry struct {
diff --git a/weed/filer2/memdb/memdb_store.go b/weed/filer2/memdb/memdb_store.go
index 5a72b7cf9..47e9934aa 100644
--- a/weed/filer2/memdb/memdb_store.go
+++ b/weed/filer2/memdb/memdb_store.go
@@ -5,6 +5,7 @@ import (
 	"github.com/google/btree"
 	"strings"
 	"fmt"
+	"time"
 )
 
 type MemDbStore struct {
@@ -37,6 +38,7 @@ func (filer *MemDbStore) AppendFileChunk(fullpath filer2.FullPath, fileChunk fil
 		return fmt.Errorf("No such file: %s", fullpath)
 	}
 	entry.Chunks = append(entry.Chunks, fileChunk)
+	entry.Mtime = time.Now()
 	return nil
 }