adjusting, seems there are some perf benefit

weed/command/mount_std.go

@@ -39,9 +39,9 @@ func runMount(cmd *Command, args []string) bool {
 		fuse.AllowOther(),
 		fuse.AllowSUID(),
 		fuse.DefaultPermissions(),
-		// fuse.MaxReadahead(1024*128), // TODO: not tested yet, possibly improving read performance
+		fuse.MaxReadahead(1024*128), // TODO: not tested yet, possibly improving read performance
 		fuse.AsyncRead(),
-		fuse.WritebackCache(),
+		// fuse.WritebackCache(),
 	)
 	if err != nil {
 		glog.Fatal(err)