dirty guestfish scripts that forget to sync will work just fine, which
can make this extra-puzzling if you are trying to debug a problem.
+=item Mount option C<-o sync> should not be the default.
+
+If you use C<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.
+
+The work around is to use C<guestfs_mount_options> and set the mount
+options that you actually want to use.
+
=item Read-only should be the default.
In L<guestfish(3)>, I<--ro> should be the default, and you should