1. A computer system comprising: a data storage medium comprising a plurality of storage devices configured to store data; and a data storage controller coupled to the data storage medium; wherein the data storage controller is configured to: receive read and write requests targeted to the data storage medium; schedule said read and write requests for processing by said plurality of storage devices; and schedule one or more proactive operations in order to minimize an occurrence of an unscheduled behavior comprising variable performance by one or more of the plurality of storage devices, wherein the variable performance comprises at least one of a relatively high response latency or relatively low throughput.