A head slider for a magnetic disk drive is provided. The head slider includes a leading edge, a trailing edge, an inner diameter side and an outer diameter side of an air bearing surface. The head slider further includes a first recess on the air bearing surface of the head slider, the first recess defining a first rail proximate the inner diameter side and a second rail proximate the outer diameter side wherein the first rail and the second rail are higher with respect to the recess and are asymmetrical with respect to each other.