Patent ID: 8839046

Claim:
In a RAID data storage system comprising a plurality of data storage physical entities arranged in an array to provide data storage and parity storage, the method comprising the steps of: assigning at least one reliability rating to various said data storage physical entities of said RAID data storage system; and in response to change, re-arranging data handling with respect to a portion of said data storage physical entities, using said assigned reliability ratings in accordance with reverse predictive failure analysis, to provide a designated cumulative reliability rating; wherein said change comprises dynamic changes to said RAID data storage system, resulting in a change to a cumulative reliability rating; and wherein said cumulative reliability rating is determined in accordance with the following equation: 1−[ PAF ( f+Δf,n+Δn )]=1−[ PAF ( f,n )+(∂ PAF/∂f )*Δ f +(∂ PAF/∂n )*Δ n] where: PAF=probability of failure of said array f=probability of failure of a physical entity n=number of drives in said array.