METHODS OF PROVIDING ACCESS TO I/O DEVICES

• US 20090307388A1
• Filed: 06/09/2009
• Published: 12/10/2009
• Est. Priority Date: 06/10/2008
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Tchapda, Yves Constantin
• Granted Patent: US 8,560,742 B2
• Time in Patent Office: Days
• US Class Current: 710/33
• CPC Class Codes: G06F 13/1642 with request queuing
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence
• CPC Class Codes: G06F 13/404 with address mapping
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0683 Plurality of storage devices
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

A method of providing one or more computing devices with access to a plurality of resources. The plurality of resources are provided by at least one physical device. The method comprises, at a first control element receiving a data packet transmitted by one of said one or more computing devices, and determining whether said data packet comprises a command including a first logical identifier identifying one of said resources. If it is determined that said data packet comprises a command including a first logical identifier a second logical identifier is obtained, the second logical identifier being associated with said first logical identifier and identifying said one of said resources. A request including said second logical identifier is transmitted to a second control element, the second control element being arranged to identify a physical device associated with said second logical identifier and to forward said request to the identified physical device.

Claims

1. A method of providing one or more computing devices with access to a plurality of resources, the plurality of resources being provided by at least one physical device, the method comprising, at a first control element:

receiving a data packet transmitted by one of said one or more computing devices;

determining whether said data packet comprises a command including a first logical identifier identifying one of said resources; and

if it is determined that said data packet comprises a command including a first logical identifier;

obtaining a second logical identifier, the second logical identifier being associated with said first logical identifier and identifying said one of said resources; and

transmitting a request including said second logical identifier to a second control element, the second control element being arranged to identify a physical device associated with said second logical identifier and to forward said request to the identified physical device.

2. A method according to claim 1, further comprising:

determining, at a switching device, whether said data packet satisfies a predetermined criterion, and forwarding said data packet to first control element if but only if it is determined that the data packet satisfies the predetermined criterion.

3. A method according to claim 2, wherein said data packet is addressed to said physical device.

4. A method according to claim 2, wherein said predetermined criterion is based upon a type of transaction with which said data packet is associated.

5. A method according to claim 2, wherein said predetermined criterion is that said data packet includes a command.

6. A method according to claim 2, further comprising:

if it is determined that said data packet does not satisfy the predetermined criterion, forwarding said data packet from said switching device to one of said physical devices.

7. A method according to claim 1, wherein:

if it is determined that said data packet comprises a command including a first logical identifier, the method further comprises validating said first logical identifier with reference to the computing device that transmitted the data packet; and

said second logical identifier is obtained only if said first logical identifier is valid.

8. A method according to claim 1, wherein said plurality of resources comprise a plurality of logical storage units.

9. A method according to claim 8, wherein each of plurality of logical storage units comprises storage provided by one or more non-volatile storage devices.

10. A method according to claim 1, wherein said plurality of resources comprise a plurality of Fibre Channel virtual ports.

11. A method according to claim 1, further comprising,

receiving data indicating a second logical identifier for each resource provided by said at least one physical device.

12. A method according to claim 11, wherein said data indicating second logical identifiers is received in response to a request from said first control element to said second control element.

13. A method according to claim 1, further comprising:

receiving data indicating relationships between said second logical identifiers and first logical identifiers associated with the or each computing device.

14. A method according to claim 13, wherein said data indicating relationships between said second logical identifiers and said first logical identifiers is based upon user input.

15. A method according to claim 1, wherein a plurality of computing devices are provided with access to said plurality of resources and said first control element receives respective data packets from each of said plurality of computing devices.

16. A method according to claim 15, wherein obtaining a second logical identifier associated with said first logical identifier is based upon an identity of a computing device from which a respective data packet is received.

17. A method according to claim 1, further comprising:

storing data at the first control element defining relationships between said second logical identifiers and first logical identifiers associated with the or each computing devices.

18. A method according to claim 1, further comprising:

storing data defining a plurality of relationships between at least one first logical identifier and a plurality of second logical identifiers, wherein each of said plurality of relationships is associated with a respective computing device.

19. A method according to claim 1, wherein said data packets are PCI data packets.

20. A method according to claim 1, wherein said command including a first logical identifier is selected from the group consisting of a SCSI command a SAS command and a SATA command.

21. A method according to claim 1, wherein said second control element is a host bus adapter.

22. A method according to claim 1, wherein said first control element stores data received from said at least one computing device.

23. A method according to claim 22, wherein the first control element provides said stored data to said physical device in response to requests from said physical device.

24. A method according to claim 23, wherein said physical device comprises a plurality of physical devices, at least one of which is a storage device, and at least one of which is a device other than a storage device.

25. A method of providing one or more computing devices with access to a plurality of resources, the plurality of resources being provided by at least one physical device, the method comprising:

connecting said one or more computing devices and said at least one physical device to a switching device arranged to allow data to pass between said one or more computing devices and said one or more physical devices;

receiving at the switching device a data packet sent by one of said one or more computing devices and addressed to one of said at least one physical devices;

determining whether the received data packet satisfies a predetermined criterion; and

if said data packet satisfies said predetermined criterion, directing said data packet to a control element;

wherein the control element is arranged to carry out a method according to claim 1.

26. A computer program comprising computer readable instructions arranged to control a processor to carry out a method according to claim 1.

27. A computer readable medium carrying a computer program according to claim 26.

28. A control element for providing one or more computing devices with access to a plurality of resources, the plurality of resources being provided by at least one physical device, the apparatus comprising:

an interface arranged to receive a data packet transmitted by one of said one or more computing devices;

a processor arranged to determine whether said data packet comprises a command including a first logical identifier identifying one of said resources, wherein if it is determined that said data packet comprises a command including a first logical identifier;

the processor is arranged to obtain a second logical identifier, the second logical identifier being associated with said first logical identifier and identifying said one of said resources;

an interface arranged to transmit a request including said second logical identifier to a further control element if it is determined that said data packet comprises a command including a first logical identifier identifying one of said resources, the further control element being arranged to identify a physical device associated with said second logical identifier and to forward said request to the identified physical device.

29. Apparatus for providing one or more computing devices with access to a plurality of resources, the apparatus comprising:

a control element according to claim 28, in communication with a switching device, wherein the switching device is arranged to determine whether said data packet satisfies a predetermined criterion, and to forward said data packet to said control element if but only if it is determined that the data packet satisfies the predetermined criterion.

30. Apparatus according to claim 29, wherein the switching device is further arranged to forward said data packet from said switching device to one of said physical devices

if it is determined that said data packet does not satisfy the predetermined criterion.

31. Apparatus according to claim 28, wherein said plurality of resources comprise a plurality of logical storage units.

32. Apparatus according to claim 31, wherein each of the plurality of logical storage units comprises storage provided by one or more non-volatile storage devices.

33. Apparatus according to claim 28, wherein said plurality of resources comprise a plurality of Fibre Channel virtual ports.