System and method for concurrent logical device swapping

• US 7,085,956 B2
• Filed: 04/29/2002
• Issued: 08/01/2006
• Est. Priority Date: 04/29/2002
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Shannon, Michael J., Yudenfriend, Harry M., Petersen, David B.
• Primary Examiner(s): Baderman, Scott
• Assistant Examiner(s): CONTINO, PAUL F
• Application Number:
  US10/134,254
• Publication Number:
  US 20030204772A1
• Time in Patent Office: 1,555 Days
• Field of Search: 714/4, 714/6, 714/47, 714/7, 711/112, 711/114
• US Class Current: 714/6.31
• CPC Class Codes: G06F 11/2069 Management of state, configuration or failover
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• 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: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0632 by initialisation or re-initialisation of storage systems
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability

Abstract

A system and method for concurrently performing logical device swaps for at least one logical subsystem, comprising: concurrently performing the following for each logical subsystem of each computer system prior to the occurrence of an event calling for logical device swaps—receiving a list of data storage device pairs, each pair comprising a first device and a corresponding second device and placing each listed second data storage device into a pseudo-online state; and concurrently performing the following for each logical subsystem of each computer system upon the occurrence of an event calling for logical device swaps—replacing a binding to each listed first device with a binding to each corresponding listed second device, wherein the binding causes I/O requests to be directed to the listed first device prior to the replacement, and further wherein the binding causes I/O requests to be directed to the corresponding listed second device subsequent to the replacement.

Claims

1. A method of performing concurrent logical device swapping for at least one logical subsystem of at least one computer system, each said logical subsystem including at least one pair of devices, the method comprising:

performing an initialization for said logical subsystem, the initialization including;

receiving a list of data storage device pairs, each said pair comprising a first device and a corresponding second device, and

placing each said listed second data storage device into a pseudo-online state; and

concurrently performing a logical swap for one or more of each said logical subsystems of one or more of each said computer systems, the logical swap including;

concurrently replacing a binding to each said listed first device with a binding to each said corresponding listed second device, wherein said binding causes I/O requests to be directed to said listed first device prior to said replacement, and further wherein said binding causes I/O requests to be directed to said corresponding listed second device subsequent to said replacement.

2. A method as in claim 1 wherein said initialization is performed concurrently for multiple logical subsystems and multiple computer systems.

3. A method as in claim 1 wherein said logical swap is performed concurrently for multiple logical subsystems and multiple computer systems.

4. A method as in claim 1 further comprising:

synchronizing I/O activity among said listed first and second devices;

unbinding aliases to said listed first devices; and

binding said unbound aliases to said listed second devices.

5. A method as in claim 1 wherein said placing each said listed second device into a pseudo-online state further comprises marking said listed second devices as in use, whereby said marking prevents execution of additional I/O requesis, said I/O requests being issued subsequent to said marking.

6. A method as in claim 1 wherein said logical swapping is performed by a processor, said processor being in communication with said logical subsystem, said communication via a data communications link.

7. A method as in claim 6 wherein said logical swapping is performed by a processor being located in a geographically separate location from said first devices and from said second devices.

8. A method as in claim 6 wherein said processor executes a mainframe operating system.

9. A method as in claim 1 wherein said swaps occur prior to and without causing an application or data request time-out.

10. A method as in claim 1 wherein said swaps occur without causing an application or data request error.

11. A storage medium encoded with machine-readable computer program code for performing concurrent logical device swapping for at least one logical subsystem, each said logical subsystem including at least one pair of devices, the storage medium including instructions for causing a processor to implement a method comprising:

performing an initialization for each logical subsystem of each computer system, the initialization including;

receiving a list of data storage device pairs, each said pair comprising a first device and a corresponding second device, and

placing each said listed second data storage device into a pseudo-online state; and

concurrently performing a logical swap for one or more of each said logical subsystems of one or more of each said computer systems, the logical swap including;

concurrently replacing a binding to each said listed first device with a binding to each said corresponding listed second device, wherein said binding causes I/O requests to be directed to said listed first device prior to said replacement, and further wherein said binding causes I/O request to be directed to said corresponding listed second device subsequent to said replacement.

12. A storage medium as in claim 11 wherein said initialization is performed concurrently for multiple logical subsystems.

13. A storage medium as in claim 11 wherein said logical swap is performed concurrently for multiple logical subsystems.

14. A system for performing concurrent logical device swapping, the system comprising:

at least one logical subsystem of at least one computer system, each said logical subsystem including at least one pair of data storage devices; and

a processor for implementing a method comprising;

performing an initialization for said logical subsystem, the initialization including;

receiving a list of the data storage device pairs, each said pair comprising a first device and a corresponding second device, and

placing each said listed second data storage device into a pseudo-online state; and

concurrently performing a logical swap for one or more of each said logical subsystems of each said computer systems, the logical swap including;

concurrently replacing a binding to each said listed first device with a binding to each said corresponding listed second device, wherein said binding causes I/O requests to be directed to said listed first device prior to said replacement, and further wherein said binding causes I/O requests to be directed to said corresponding listed second device subsequent to said replacement.

15. A system as in claim 14 wherein said initialization is performed concurrently for multiple logical subsystems.

16. A system as in claim 14 wherein said logical swap is performed concurrently for multiple logical subsystems.

17. A system as in claim 14 wherein said processor executes a mainframe operating system.

18. A system as in claim 14 wherein said processor is located in a geographically separate location from said first device and from said second device.

19. A system as in claim 14 wherein said processor implements the method using computer program code written in at least one of the following computer programming languages;

REXX, assembly, C, C++, or Java.

20. A system as in claim 14 wherein said swaps occur prior to and without causing an application or data request time-out.

21. A system as in claim 14 wherein said swaps occur without causing an application or data request error.