Method, apparatus and program storage device for providing data path optimization

• US 7,194,662 B2
• Filed: 02/28/2003
• Issued: 03/20/2007
• Est. Priority Date: 02/28/2003
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Do, Cam-Thuy, Liu, Wenhua, Ghosalkar, Vishal, Ngo, Khoa Khon
• Primary Examiner(s): Maskulinski; Michael C.
• Application Number:
  US10/377,359
• Publication Number:
  US 20040172636A1
• Time in Patent Office: 1,481 Days
• Field of Search: 714/43
• US Class Current: 714/43
• CPC Class Codes: G06F 11/201 between storage system components
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality
• 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 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

The present invention is a method, apparatus and program storage device for providing data path optimization for redundant data paths. The present invention provides data path optimization that increases the data access throughput and availability to a device by using multiple paths when a modification event occurs.

Claims

1. A virtual device controller for multi-path operation, comprising:

a first driver for detecting a modification event on a data path;

a second driver, coupled to the first driver, for creating a redundant data path for the data path, wherein the first driver communicates the modification event to the second driver, the second driver creating the redundant data path in response to the modification event; and

a third driver for modifying the behavior of physical device hardware, wherein the third driver scans a memory including a list of devices for removing any of the devices in the list.

2. The virtual device controller of claim 1, wherein the modification event comprises a Plug and Play event.

3. The virtual device controller of claim 1, wherein the first driver provides a message to the second driver for notifying the second driver when a modification event has occurred.

4. The virtual device controller of claim 3, wherein the message includes modification event information to control multi-path access to the physical device.

5. The virtual device controller of claim 1, wherein the second driver processes a physical device object to control multi-path access.

6. The virtual device controller of claim 1 further comprising a memory including a physical device object list that is scanned by the second driver to determine when a physical device object exists for controlling multi-path access.

7. The virtual device controller of claim 1, wherein the second driver determines when a data path should be added or removed for controlling multi-path access.

8. The virtual device controller of claim 1, wherein the second driver determines when the states of a path should be updated for controlling multi-path access.

9. The virtual device controller of claim 1, wherein the second driver is configured to control redundant adapters for eliminating a single path as a single point of failure.

10. The virtual device controller of claim 1, wherein the second driver is configured for increasing availability to the physical device and improving system performance by balancing an I/O workload across multiple paths.

11. The virtual device controller of claim 1, wherein the memory further comprises a physical device object list that may be searched by the second driver to determine when a physical device object (PDO) exists for the physical device.

12. The virtual device controller of claim 1, wherein the memory further includes a functional device object (FDO) with a physical device object (PDO) when the PDO exists, else a new PDO to register the FDO with.

13. The virtual device controller of claim 1, wherein the memory location further comprises a physical device object list, the physical device object list contains an indication of PDOs to be removed.

14. The virtual device controller of claim 1, wherein the first driver creates a functional device object (FDO) for the physical device.

15. The virtual device controller of claim 1, wherein the redundant data path and the data path are coupled to a same physical device in response to the modification event.

16. A cluster environment for multi-path operation, comprising:

a memory; and

a plurality of hosts, wherein each host includes a virtual device controller comprising;

a first driver for detecting a modification event on a data path;

a second driver, coupled to the first driver, for creating a redundant data path for the data path, wherein the first driver communicates the modification event to the second driver, the second driver creating the redundant data path in response to the modification event; and

a third driver for modifying the behavior of physical device hardware, wherein the third driver scans the memory including a list of devices for removing any of the devices in the list.

17. A virtual device controller for multi-path operation, comprising:

a first means for detecting a modification event on a data path;

a second means, coupled to the first means, for creating a redundant data path for the data path, wherein the first means communicates the modification event to the second means, the second means creating the redundant data path in response to the modification; and

a third means for modifying the behavior of physical device hardware, wherein the third means scans a memory including a list of devices for removing any of the devices in the list.