A data storage system includes a host system configured to provide an I/O request stream and a data storage subsystem. The data storage subsystem has a data storage device and a processor. The processor is configured to provide streaming data in response to the I/O request stream, determine a current streaming rate of the I/O request stream, and determine a time-based read ahead size based on a time ahead duration and the current streaming rate of the I/O request stream. The time-based read ahead size may be updated while streaming, for example, after a delay period.