System for I/O path load balancing and failure which can be ported to a plurality of operating environments

• US 6,341,356 B1
• Filed: 03/25/1999
• Issued: 01/22/2002
• Est. Priority Date: 03/25/1999
• Status: Expired due to Term

• Current Assignee: X Corp. (f/k/a Twitter, Inc.) (X Holdings Corp.)
• Original Assignee: International Business Machines Corporation
• Inventors: Do, Cam-Thuy, Shaw, Limei, Johnson, Richard Harold
• Primary Examiner(s): Ray, Gopal C.
• Application Number:
  US09/276,618
• Time in Patent Office: 1,034 Days
• Field of Search: 714/4, 714/5, 714/7, 714/38, 714/40, 714/43, 714/44, 709/301, 709/302, 709/105, 711/114, 711/203, 710/37, 710/17, 710/38, 710/74, 710/63, 710/72, 710/3, 710/111, 370/351
• US Class Current: 714/4.1
• CPC Class Codes: G06F 11/2007 using redundant communication media
• CPC Class Codes: G06F 11/201 between storage system components
• CPC Class Codes: G06F 11/2053 where persistent mass storage functionality or persistent mass storage control functionality is redundant error detection or correction in information storage based on relative movement between record carrier and transducer G11B20/18
• CPC Class Codes: G06F 13/102 where the programme performs an interfacing function, e.g. device driver G06F13/105 takes precedence; scheduling within device drivers G06F9/52; contention policies within device drivers G06F9/4881
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

A method and system for path management of data processing in an environment which includes a plurality of hosts running multiple operating systems is disclosed. The method and system includes providing a portable path management code and providing a plurality of control modules. Each of the control modules has an area which can only be accessed by the portable path management code. The method and system also include providing an interface to at least one device driver from the portable management code to allow the portable management code to control access to plurality of paths to a plurality of storage subsystems by the at least one device driver. The method and system in accordance with the present invention can provide path load balancing and fail over for a plurality of paths to a plurality of storage subsystems. The path management code is portable and platform independent so that the functionality can be ported easily to each operating system in the multiple system environment.

Claims

1. A method for path management of a data processing system which can include a plurality of hosts;

the plurality of hosts running multiple operating systems, the method comprising the steps of;

(a) providing a portable path management code;

(b) providing a plurality of control modules, each of the control modules having an area which can only be accessed by the portable path management code; and

(c) providing an interface to at least one device driver from the portable management code to allow the portable management code to control access to the plurality of paths to a plurality of storage subsystems by the at least one device driver.

2. The method of claim 1, wherein the portable path management code providing step (a) further includes the step of:

(a1) providing a platform independent portable path management code.

3. The method of claim 1 wherein the portable path management code controls access to the plurality of paths by selecting a path of the plurality of paths on a global round robin basis.

4. The method of claim 3 wherein the portable path management code further controls access to the plurality of paths by selecting a new path of the plurality of paths if the path fails.

5. A system for path management in a host including at least one device, at least one device driver for controlling the at least one device, and a plurality of paths between the at least one device and the at least one device driver, the system comprising:

a portable management code for managing the plurality of paths;

at least one control structure having at least one data structure accessible to the portable management code, the at least one data structure including information about the plurality of paths and the at least one device; and

at least one interface to the at least one device driver from the portable management code, the at least one interface allowing the portable management code to control access to plurality of paths to the at least one device by the at least one device driver.

6. The system of claim 5 wherein the portable management code is platform independent.

7. The system of claim 5 wherein the at least one interface is platform specific.

8. The system of claim 5 wherein the portable management code further selects a path of the plurality of paths for providing input to or output from the at least one device.

9. The system of claim 8 wherein the portable management code further selects a new path of the plurality of paths when the path fails.

10. A computer-readable medium containing a program for servicing a request for at least one device, a plurality of paths being coupled to the at least one device, the program including instructions for:

(a) selecting a path of the plurality of paths; and

(b) providing the selected path to an interface, the interface for communicating with a device driver for servicing the request;

wherein the program is portable.

11. The computer-readable medium of claim 10 wherein the instruction for selecting the path further includes instructions for:

(a1) selecting the path on a global round robin basis.

12. The computer-readable medium of claim 10 wherein the program further includes instructions for:

(c) accounting for a failure of the selected path.

13. The computer-readable medium of claim 12 wherein the instruction for accounting for a failure of the selected path further includes instructions for:

(c1) selecting a new path of the plurality of paths; and

(c2) providing the new path to the interface.