US Patent 8239589 Balancing latency and throughput for shared resources

Input and output (I/O) operations performed by a data storage device are managed dynamically to balance aspects such as throughput and latency. Sequential read and write requests are sent to a data storage device whereby the corresponding operations are performed without time delay due to extra disk revolutions. In order to minimize latency, particularly for read operations, random read and write requests are held in a queue upstream of an I/O controller of the data storage device until the buffer of the data storage device is empty. The queued requests can be reordered when a higher priority request is received, improving the overall latency for specific requests. An I/O scheduler of a data server is still able to use any appropriate algorithm to order I/O requests, such as by prioritizing reads over writes as long as the writes do not back up in the I/O queue beyond a certain threshold.