Data storage systems using time-based read ahead

1. A data storage system comprising:

a host system configured to provide an I/O request stream comprising a plurality of I/O requests; and

a data storage subsystem comprising a data storage device and a processor configured to:

provide streaming data to the host system in response to the I/O request stream;

determine a current streaming rate of the I/O request stream;

determine a time-based read ahead size based on a time ahead duration and the current streaming rate of the I/O request stream; and

set a read ahead cache size of the data storage subsystem to buffer the streaming data in memory based on the time-based read ahead size.

2. The system of claim 1 , wherein the time-based read ahead size is variable in response to the time ahead duration being static and the current streaming rate being variable.

3. The system of claim 1 , wherein the processor is further configured to update the current streaming rate while providing streaming data based on the I/O request stream.

4. The system of claim 1 , wherein the processor is further configured to wait a predetermined delay after beginning to receive the I/O request stream to determine the time-based read ahead size.

5. The system of claim 1 , wherein the processor is further configured to determine the time ahead duration based on a streaming parameter, the streaming parameter based on one or more of: a target stream quality, a target frame rate, a user input, an encoding scheme, a type of file, and a compression configuration.

6. The system of claim 1 , wherein the processor is further configured to determine the time ahead duration based on a storage subsystem parameter, the storage subsystem parameter based on one or more of: a system configuration, a system latency, and a latency probability.

7. The system of claim 1 , wherein the processor is further configured to:

determine a rate of I/O requests and one or more I/O sizes associated with the I/O request stream; and

determine the current streaming rate of the I/O request stream based on the time ahead duration, the rate of I/O requests, and the one or more I/O sizes.

8. The system of claim 1 , wherein the processor further configured to:

determine a tail latency based on one or more latencies of the data storage subsystem; and

set the time ahead duration to a value equal to or greater than the tail latency.

9. The system of claim 1 , wherein the time ahead duration is less than or equal to 500 milliseconds.

10. A method comprising:

providing data to a host system in response to an I/O request stream comprising a plurality of I/O requests;

determining a current streaming rate of the I/O request stream;

determining a time-based read ahead size based on a predetermined time ahead duration and the current streaming rate of the I/O request stream; and

setting a read ahead cache size of a data storage subsystem to buffer the streaming data in memory based on the time-based read ahead size.

11. The method of claim 10 , wherein the time-based read ahead size is variable in response to the time ahead duration being static and the current streaming rate being variable.

12. The method of claim 10 , further comprising updating the current streaming rate while providing streaming data based on the I/O request stream.

13. The method of claim 10 , further comprising waiting a predetermined delay in response to receiving the I/O request stream to determine the time-based read ahead size.

14. The method of claim 10 , further comprising determining the time ahead duration based on a streaming parameter, the streaming parameter based on one or more of: a target stream quality, a target frame rate, a user input, an encoding scheme, a type of file, and a compression configuration.

15. The method of claim 10 , further comprising determine the time ahead duration based on a storage subsystem parameter, the storage subsystem parameter based on one or more of: a system configuration, a system latency, and a latency probability.

16. A data storage subsystem comprising:

a data storage device comprising data; and

a processor configured to:

provide data to a host system in response to an I/O request stream comprising a plurality of I/O requests;

determine a current streaming rate of the I/O request stream;

determine a time-based read ahead size based on a predetermined time ahead duration and the current streaming rate of the I/O request stream; and

set a read ahead cache size of the storage subsystem to buffer the streaming data in memory based on the time-based read ahead size.

17. The system of claim 16 , wherein the time-based read ahead size is variable in response to the time ahead duration being static and the current streaming rate being variable.

18. The system of claim 16 , wherein the processor is further configured to update the current streaming rate while providing streaming data based on the I/O request stream.

19. The system of claim 16 , wherein the processor is further configured to wait a predetermined delay after beginning to receive the I/O request stream to determine the time-based read ahead size.

20. The system of claim 16 , wherein the processor is further configured to determine the time ahead duration based on a streaming parameter, the streaming parameter based on one or more of: a target stream quality, a target frame rate, a user input, an encoding scheme, a type of file, and a compression configuration.

21. The system of claim 16 , wherein the processor is further configured to determine the time ahead duration based on a storage subsystem parameter, the storage subsystem parameter based on one or more of: a system configuration, a system latency, and a latency probability.