1. A storage array, comprising: a plurality of directors, each having at least one processor thereon; a global memory distributed among the plurality of directors, wherein a portion of the global memory is provided on each of the directors, and wherein the portion of the global memory on each director is accessible by other of the directors; a interconnect fabric coupled to each of the directors, wherein global memory accesses performed by one director to access the portion of the global memory provided on another director are through the interconnect fabric; a plurality of partitioned storage subsystems, each including a separate subset of the directors, wherein each of the partitioned storage subsystems handles I/O operations for a plurality of logical devices independently of other I/O operations for logical devices of other ones of the partitioned storage subsystems; and a mechanism that, for each of the I/O operations, determines a particular one of the partitioned storage subsystems to handle a particular one of the I/O operations, wherein the particular one of the partitioned storage subsystems is determined according to metadata that is provided in the portion of the global memory provided on a corresponding director that corresponds to the particular one of the I/O operations, wherein the corresponding director is included in the particular one of the partitioned storage subsystems, wherein the metadata contains information that correlates logical device data with physical device data, and wherein the mechanism transfers a handling request for the particular one of the I/O operations to the particular one of the partitioned storage subsystems.