diff --git a/weed/storage/volume_vacuum.go b/weed/storage/volume_vacuum.go
index f3aa5f1cb..e5d932c9e 100644
--- a/weed/storage/volume_vacuum.go
+++ b/weed/storage/volume_vacuum.go
@@ -314,7 +314,7 @@ func (v *Volume) copyDataAndGenerateIndexFile(dstName, idxName string, prealloca
 	var (
 		dst, idx *os.File
 	)
-	if dst, err = createVolumeFile(dstName, preallocate, v.MemoryMapMaxSizeMb); err != nil {
+	if dst, err = createVolumeFile(dstName, preallocate, 0); err != nil {
 		return
 	}
 	defer dst.Close()