Method and apparatus for high-speed access to and sharing of storage devices on a networked digital data processing system

• US 6,694,317 B1
• Filed: 11/08/2000
• Issued: 02/17/2004
• Est. Priority Date: 12/31/1997
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Stearns, Kevin M., Stakutis, Christopher J.
• Primary Examiner(s): Mizrahi, Diane D.
• Assistant Examiner(s): MOFIZ, APU M
• Application Number:
  US09/708,785
• Time in Patent Office: 1,196 Days
• Field of Search: 707/10, 707/104.1, 709/221, 709/227, 705/77
• US Class Current: 709/227
• CPC Class Codes: G06F 16/1824 implemented using Network-attached Storage [NAS] architecture distributed or networked storage systems G06F3/067; protocols for distributed storage of data in a network H04L67/1097
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• 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]
• CPC Class Codes: Y10S 707/922 Communications
• CPC Class Codes: Y10S 707/959 Network
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing

Abstract

A digital data processing system with improved access to information stored on a peripheral device is provided. The system has a plurality of nodes, a peripheral device, a file system and a bypass mechanism. A first node (e.g., a client node) is connected to a second node (e.g., a server node) over a first communications pathway (e.g., a network). The second node is itself connected to a peripheral device (e.g., a disk drive) over a second communications pathway. The first node, too, is connected to the peripheral device over a third communications pathway. The file system, executing on the first and second nodes, is capable of responding to access requests generated by the first node for transferring data between that node and the peripheral device, via the second node and via the first and second communications pathways. The file system also maintains administrative information pertaining to storage on the peripheral device of data designated by such requests. That information includes, for example, physical storage location mappings for files and other data stored on the peripheral device. The bypass mechanism, which executes on at least the first node, intercedes in the response to at least selected input/output, or access, requests generated by that node. The bypass transfers data designated by such requests between the first node and the peripheral device over the third communications pathway, in lieu of transferring that data via the second node and the first and second communications pathways. Such transfers by the bypass, however, are made using the administrative information maintained by the file system relating to storage of such data on the peripheral device.

Claims

1. A digital data processing system with improved access to information stored on a peripheral device, comprising

A. first and second nodes coupled to one another,

B. at least the second node being coupled to a peripheral device,

C. a file system, executing on the first and second nodes, the file system being capable of responding to access requests generated by the first node, for

(i) transferring data designated by the request between the first node and the peripheral device over a first communications pathways,

(ii) maintaining administrative information pertaining to storage of the data designated by the request on the peripheral device,

D. a first bypass, executing on at least the first node, for interceding in response to at least a first selected access request applied thereby to the file system, by transferring data designated by that request between the first node and the peripheral device over a second communications pathway in accord with administrative information maintained by the file system pertaining to storage of that data on the peripheral storage device.

2. A digital data processing system according to claim 1, wherein the transfer of data by the first bypass over the second communications pathway obviates transfer of such data over the first communications pathway.

3. A digital data processing system according to claim 1, wherein the first bypass transfers the designated data over the second communications pathway with physical storage locations on the peripheral device determined from the administrative information for that data maintained by the second node.

4. A digital data processing system according to claim 3, wherein the first bypass obtains from the second node administrative information from which can be determined physical storage locations in the peripheral device for the data designated by the first request.

5. A digital data processing system according to claim 4, wherein the first bypass at least initiates obtaining administrative information from the second node by generating and applying to the file system a second access request, the second request being for access to a logical unit to which access is controlled by the second node.

6. A digital data processor according to claim 5, wherein the second request is for access to a logical unit other than a file designated in the first access request.

7. A digital data processing system according to claim 6, wherein the logical unit is a file that resides on a peripheral device local to the first node.

8. A digital data processor according to claim 7, wherein the request generated by the first bypass is a request to write and a file.

9. A digital data processing system according to claim 6, comprising a second bypass, executing on the second node, for responding to the second access request by obtaining from the second node, and for at least temporarily retaining, a physical mapping for a file designated by the first access request.

10. A digital data processing system according to claim 9, wherein the first bypass obtains the physical mapping for the file designated by the first access request by generating and applying to the file system a third access request for access, the third request designating the logical unit designated by the second access request.

11. A digital data processing system according to claim 4, wherein

A. the first bypass generates and applies to the file system a second access request, the second access request being a request for writing to a logical unit an identifier of a file designated by the first access request, the logical unit being a file to which access is controlled by the second node but which is other than the file designated in the first access request,

B. the second bypass responds to the second access request by reading the logical unit to determine the identifier, obtaining from the second node a physical mapping for a file designated by that identifier, and writing that physical mapping to the logical unit, and

C. the first bypass generates and applies to the file system a third access request for access, the third request being a request for the physical mapping from the logical unit.

12. A digital data processing system according to claim 11, wherein the second communications pathway comprises any of a fibre channel, a firewire bus, a serial storage architecture (SSA) bus, high-speed Ethernet bus, high performance parallel interface (HPPI) bus.

13. A digital data processing system according to claim 1, wherein the first bypass selectively limits transfers between the first node and the peripheral device over the second communications pathway.

14. A digital data processing system according to claim 13, wherein the first bypass selectively limits such transfers to facilitate access to the peripheral device by a node other than the first node.

15. A digital data processing system according to claim 14, wherein the bypass limits such transfers in accord with a predefined throttling limit.

16. A digital data processing system according to claim 1, wherein the first communications pathway comprises any of a wide area network interconnect, local area network interconnect, internet interconnect, or other network interconnect.

17. A method for improved access to a peripheral device in a digital data processing system of the type having

first and second nodes coupled to one another,

a file system, executing on the first and second nodes, being capable of responding to access requests generated by the first node, for (i) transferring data designated by the request between the first node and the peripheral device over a first communications pathways, and (ii) maintaining administrative information pertaining to storage of the data designated by the request on the peripheral device,

the improvement comprising interceding in response to at least a first selected access request generated by the first node by transferring data designated by that request between the first node and the peripheral device over a second communications pathway in accord with administrative information maintained by the file system pertaining to storage of that data on the peripheral storage device.

18. A method according to claim 17, wherein the transfer of data over the second communications pathway obviates transfer of such data over the first communications pathway.

19. A method according to claim 17, wherein the interceding step comprises transferring the designated data over the second communications pathway to physical storage locations on the peripheral device determined from the administrative information for that data maintained by the second node.

20. A method according to claim 19, wherein the interceding step comprises at least initiating the obtaining of administrative information from the second node by generating and applying to the file system a second access request, the second request being for access to a logical unit to which access is controlled by the second node.

21. A method according to claim 20, wherein the second request is for access to a logical unit other than a file designated in the first access request.

22. A method according to claim 21, wherein the logical unit is a file that resides on a peripheral device local to the first node.

23. A method according to claim 22, wherein the request generated by the first bypass is a request to write a file.

24. A method according to claim 23, wherein the interceding step comprises transferring, to the first node, the physical mapping for the file designated by the first access request by generating and applying to the file system a third access request for access, the third request designating the logical unit designated by the second access request.

25. A method according to claim 19, comprising responding to the second access request by obtaining from the second node, and at least temporarily retaining on any of the second node and the peripheral device, a physical mapping for a file designated by the first access request.