Prioritized access for media with heterogeneous access rates

Abstract

A non-volatile storage subsystem is described which identifies performance-sensitive commands and heterogeneous performance characteristics of portions of a non-volatile storage media, and matches the performance sensitivity of the commands with an available physical write address corresponding to performance characteristics appropriate for the performance sensitivity of the command. A command can be considered performance sensitive if it originates from a host or a preferred host among a plurality of hosts, or if the command designates a frequently accessed logical address. Performance characteristics of the storage device can be determined by physical architectures of the storage media such as the distance from the axial center of a disk media, or the architecture technology of a solid-state array. Performance characteristics can also be determined dynamically and heterogeneous performance can be encouraged by internal maintenance policies of the subsystem.