Stream-Oriented Interconnect for Networked Computer Storage

• US 20060233170A1
• Filed: 06/23/2006
• Published: 10/19/2006
• Est. Priority Date: 05/17/2001
• Status: Active Grant

• Current Assignee: Dan Avida, Serge Plotkin
• Original Assignee: Dan Avida, Serge Plotkin
• Inventors: Plotkin, Serge, Avida, Dan
• Granted Patent: US 7,944,936 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 45/10 Routing in connection-oriented networks, e.g. X.25 or ATM
• CPC Class Codes: H04L 45/46 Cluster building
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/357 Fibre channel switches
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 11/0071 Provisions for the electrical-optical layer interface
• CPC Class Codes: H04Q 2011/0015 using splitting combining
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/003 using switches based on microelectro-mechanical systems [MEMS]
• CPC Class Codes: H04Q 2011/0069 using dedicated optical channels
• CPC Class Codes: H04Q 2011/0084 Quality of service aspects
• CPC Class Codes: Y10S 370/912 Packet communications

Abstract

An apparatus and method for connecting a plurality of computing devices, e.g. web servers, database servers, etc., to a plurality of storage devices, such as disks, disk arrays, tapes, etc., by using a stream-oriented (circuit oriented) switch that has high throughput, but that requires non-negligible time for reconfiguration is disclosed. An example of such stream-oriented switch is an optical switch. The preferred embodiment comprises a plurality of communication ports for connection to servers, and a plurality of ports for connection to storage devices. The system decodes the requests from the computing devices and uses this information to create circuits, e.g. optical paths in embodiments where the stream-oriented switch is an optical switch, through the stream-oriented switch. The system uses these circuits to route traffic between the computing devices and the storage devices. Buffering of data and control in the device memory is used to improve overall throughput and reduce the time spent on reconfigurations. An alternative embodiment of the system uses two interconnects, in which all devices are connected to one or both interconnects. One of the interconnects is the stream-oriented switch described above. The second interconnect is a conventional packet switch which can switch traffic on a packet-by-packet basis, e.g. electronic packet switch. In contrast to the stream-oriented switch, the packet switch has much smaller overall throughput, but requires much less time for reconfiguration. The stream-oriented switch is used for switching relatively large data streams, e.g. reading a large file, while the packet switch is used for control and the rest of the data traffic.

Claims

1. A stream-oriented switch, comprising:

a plurality of communication ports for connection to any of a plurality of computing devices and a plurality of ports for connection to any of a plurality of storage devices; and

means for decoding requests from any of said computing devices and/or storage devices and for using information from said decoded requests to route traffic between any of said computing devices and said storage devices.

2. The apparatus of claim 1, wherein said stream-oriented switch is an optical switch.

3. The apparatus of claim 1, further comprising:

at least two interconnects;

wherein all devices are connected to at least one of said interconnects;

wherein one of said interconnects comprises said stream-oriented switch;

wherein at least a second interconnect comprises a conventional packet switch which can switch traffic on a packet-by-packet basis; and

wherein said stream-oriented switch is used for switching relatively large data streams, while said packet switch is used for control and the rest of data traffic.

4. The apparatus of claim 3, further comprising any of:

a statistical prediction algorithm for predicting traffic flows; and

a statistical decision algorithm for deciding on how to reconfigure said stream-oriented switch in real time.

5. The apparatus of claim 4, wherein certain selected measures are optimized by configuring said stream-oriented switch for routing said predicted traffic flow, and wherein a remainder of predicted traffic that could not be accommodated by said stream-oriented switch, as well as unpredicted traffic, through said packet switch.

6. The apparatus of claim 4, wherein said statistical prediction algorithm comprises a Hidden Markov Model;

and wherein said statistical decision algorithm comprises a Markov Decision Process.

7. An optical switch comprising:

a switch control unit for configuring said optical switch, wherein any of a plurality of computing devices and storage devices are interconnected by circuits that are available through said optical switch as a result of said optical switch configuration.

8. The apparatus of claim 7, further comprising:

a scheduling and load balancing unit for determining a performance enhancing packet schedule and routing, for generating information used in determining switch configuration, for distributing a communication load among various available links between any of said computing devices and said storage devices, and for ordering packet flows

9. The apparatus of claim 7, further comprising:

a packet scheduling unit for sending a transmission schedule to said computing devices and said storage devices, as well as to said system controller.

10. The apparatus of claim 7, said optical switch comprising a multiple fabric switch for connecting said computing devices and said storage devices.

11. The apparatus of claim 9, wherein all said devices are connected to at least one of an electronic packet switch and an optical switch;

wherein said packet switch is used for control and a portion of data traffic;

wherein said optical switch is used for a remainder of said data traffic; and

wherein said multiple fabrics are controlled by said system control unit which receives and issues control and status information via said packet switch, and which is responsible for configuring said optical switch.

12. The apparatus of claim 11, wherein said scheduling and load balancing unit distributes a communication load between available links through said fabrics which connect said computing devices and said storage devices by recommending to said system controller unit a configuration of said optical switch and said packet switch that divides traffic between said fabrics based upon selected criteria.

13. The apparatus of claim 12, wherein said selected criteria comprise any of throughput and delay.

14. The apparatus of claim 7, further comprising any of:

a buffer for aggregating multiple data write requests; and

a data caching and predictive data read-ahead mechanism;

wherein amount of data that can be transferred through said optical switch between reconfigurations is increased.

15. The apparatus of claim 7, further comprising:

a transaction prediction system that predicts future behavior of said computing devices and said storage devices based on prior transactions and known behavior patterns.

16. The apparatus of claim 15, wherein said transaction prediction system builds and continually adapts a statistical model, which optionally comprises a Hidden Markov Model;

wherein said transaction prediction system improves said statistical model from time to time and uses said statistical model to enhance performance of said optical switch by making predictions about future transactions.

17. The apparatus of claim 15, wherein a decision of when and how to reconfigure said optical switch is made using a Markov Decision Process.

18. The apparatus of claim 15, wherein a maintained statistical model is used to predict an expected benefit of each possible reconfiguration decision at every step, and to choose a preferred reconfiguration or reconfiguration sequence.

19. The apparatus of claim 7, further comprising:

means for detecting instances where data are distributed among said storage devices in a less than optimal way; and

means for dynamically rearranging data stored on said storage devices.

20. The apparatus of claim 19, further comprising:

an adaptive statistical access model for analyzing data redistribution advantages and disadvantages and for deciding whether to relocate said data and, if so, where to relocate said data.