=item Mount option C<-o sync> should not be the default.
+I<Update:> L</guestfs_mount> no longer adds any options starting
+from libguestfs 1.13.16. This section only applies to older versions.
+
If you use L</guestfs_mount>, then C<-o sync,noatime> are added
implicitly. However C<-o sync> does not add any reliability benefit,
but does have a very large performance impact.