1. An apparatus comprising a non-volatile memory resident in a data storage device, the non-volatile memory comprising a rewritable in-place memory cell having a read-write asymmetry, the read-write asymmetry corresponding with a settle time after a data write to the rewritable in-place memory cell, the non-volatile memory divided by a selection module of the data storage device into a first group of tiers prior to an event and into a second group of tiers after the event, the first and second groups of tiers being different.