According to one embodiment, there is provided a method, implemented in a magnetic disk drive, for adjusting a linear recording density. The method obtains a first flying-dependent error sensitivity for each of two or more heads. The first flying-dependent error sensitivity represents a change in read error rate corresponding to a change in flying height of the head during write. In addition, the method reduces the linear recording density of a first recording surface associated with a first head of the two or more heads if the first flying-dependent error sensitivity is a second flying-dependent error sensitivity higher than a threshold and corresponds to the first head.