Continuously available program replicas

• US 10,108,510 B2
• Filed: 05/01/2012
• Issued: 10/23/2018
• Est. Priority Date: 02/19/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Sarkar, Prasenjit, Subhraveti, Dinesh Kumar
• Primary Examiner(s): Waldron, Scott A.
• Assistant Examiner(s): Lodhi, Andalib F
• Application Number:
  US13/461,688
• Publication Number:
  US 20120221516A1
• Time in Patent Office: 2,366 Days
• Field of Search: 707610, 707615, 707626, 707636, 707655, 707659, 707660, 707679, 707640
• CPC Class Codes: G06F 11/1482 by means of middleware or OS functionality
• CPC Class Codes: G06F 11/1484 involving virtual machines
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component
• CPC Class Codes: G06F 11/2048 where the redundant components share neither address space nor persistent storage
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups

Abstract

A method for replicating a program and data storage according to one embodiment comprises sending program replication data from a first program to a second program, the second program having an application program that is a replica of an application program of the first program; sending data storage requests from the first program to a first storage system; and replicating data stored in the first storage system in a second storage system. Additional methods, systems, and computer program products are disclosed.

Claims

1. A method for replicating a program and data storage, the method comprising:

recording, as program replication data, user input to a first program by monitoring the first program and trapping system calls;

sending the program replication data from the first program to a second program such that the second program operates on the same user input as the first program, the second program having an application program that is a replica of an application program of the first program, the program replication data causing the second program to mirror a state of the first program for enabling at least one of a user and an application interaction with the second program as if it were the first program when the first program fails;

sending data storage requests from the first program to a first storage system; and

replicating data stored in the first storage system in a second storage system.

2. A method as recited in claim 1, wherein the replication data includes inputs to the first program, the second program operating on the inputs as the first program operates on the inputs.

3. A method as recited in claim 1, wherein the program replication data is used to mirror processor and memory state associated with the first program in a system running the second program, wherein the program replication data is also used to mirror any data read by the first program.

4. A method as recited in claim 1, wherein replicating data stored in the first storage system in the second storage system includes sending data storage requests from the first program to the second storage system.

5. A method as recited in claim 4, wherein the second program does not send data storage requests to the second storage system that replicates data stored in the first storage system during normal operation of the first program.

6. A method as recited in claim 4, wherein logical volume management is used to replicate the data stored in the first storage system in the second storage system.

7. A method as recited in claim 1, wherein replicating data stored in the first storage system in the second storage system includes sending data storage requests from the first storage system to the second storage system.

8. A method as recited in claim 7, wherein the second program does not send data storage requests to the second storage system that replicates data stored in the first storage system during normal operation of the first program.

9. A method as recited in claim 7, wherein the data storage requests are sent directly from the first storage system to the second storage system.

10. A method as recited in claim 1, wherein replicating data stored in the first storage system in the second storage system includes sending data storage replication data from the first program to the second program, the second program sending data storage requests to the second storage system based on the data storage replication data.

11. A method as recited in claim 1, wherein outputs of the first program are sent to at least one of the user and the application, and further comprising sending outputs of the second program to at least one of the user and the application.

12. A method as recited in claim 1, wherein, upon detecting failure of the first program, the second program suspends program replication and sends data storage requests to at least one of the first and second storage systems.

13. A method as recited in claim 1, wherein, upon detecting failure of the first storage system, the first program uses the second storage system as the primary storage system, thereby improving efficiency of a first device running the first program by reducing an amount of processing power and run time consumed by the first device in order to maintain operation following the failure of the first storage system.

14. A method as recited in claim 1, wherein a failure to transfer program replication data from the first program to the second program is interpreted by the first program as a failure of the second program and by the second program as a failure of the first program, wherein the program states of the first and second programs then diverge, wherein the first program sends data storage requests to one of the storage systems, wherein the second program sends data storage requests to the other of the storage systems.

15. A method as recited in claim 14, wherein, upon resuming transfer of program replication data from the first program to the second program, the first and second programs synchronize, wherein the first and second storage systems synchronize such that data stored on one of the storage systems during the failure is replicated on the other storage system.

16. A method as recited in claim 1, wherein a failure to replicate data stored in the first storage system in the second storage system is interpreted by the first program as a failure of the second storage system and by the second program as a failure of the first storage system, wherein the program states of the first and second programs then diverge, wherein the first program sends data storage requests to the first storage system and the second program sends data storage requests to the second storage system upon diverging.

17. A computer program product for replicating a program and data storage, the computer program product comprising:

a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising;

computer readable program code configured to record, as program replication data, user input to a first program by monitoring the first program and trapping system calls;

computer readable program code configured to send the program replication data from the first program to a second program such that the second program operates on the same user input as the first program, the second program having an application program that is a replica of an application program of the first program;

computer readable program code configured to send data storage requests from the first program to a first storage system;

computer readable program code configured to send data storage replication data from the first program to the second program, the second program sending data storage requests to a second storage system based on the data storage replication data for replicating data stored in the first storage system in the second storage system,

wherein the program replication data enables mirroring of processor and memory state associated with the first program, wherein the program replication data further enables mirroring of any data read by the first program,

computer readable program code configured to send outputs of the first program to at least one of a user and an application; and

computer readable program code configured to enable interaction of at least one of the user and the application with the second program as if it were the first program when the first program fails, wherein outputs of the second program are sent to at least one of the user and the application.

18. The computer program product as recited in claim 17, wherein, upon detecting failure of the first program, the second program suspends program replication and sends data storage requests to at least one of the first and second storage systems.

19. The computer program product as recited in claim 17, wherein, upon detecting failure of the first storage system, the first program uses the second storage system as the primary storage system, thereby improving efficiency of a first device running the first program by reducing an amount of processing power and run time consumed by the first device in order to maintain operation following the failure of the first storage system.

20. The computer program product as recited in claim 17, wherein a failure to transfer program replication data from the first program to the second program is interpreted by the first program as a failure of the second program and by the second program as a failure of the first program, wherein program states of the first and second programs then diverge, wherein the first program sends data storage requests to one of the storage systems, wherein the second program sends data storage requests to the other of the storage systems.

21. The computer program product as recited in claim 17, wherein the computer readable program code configured to enable the interaction of at least one of the user and the application with the second program as if it were the first program further comprises computer readable program code configured to direct inputs from the at least one of the user and the application to the second program and send the outputs of the second program to the at least one of the user and the application when the first program has failed.

22. The computer program product as recited in claim 17, wherein a failure to replicate data stored in the first storage system in the second storage system is interpreted by the first program as a failure of the second storage system and by the second program as a failure of the first storage system, wherein program states of the first and second programs then diverge, wherein the first program sends data storage requests to the first storage system, wherein the second program sends data storage requests to the second storage system.

23. A system having replicated programs and data storage, the system comprising:

a first device configured to run a first program, and record, as program replication data, user input to the first program by monitoring the first program and trapping system calls;

a second device configured to run a second program, the first device being configured to send the program replication data to the second device when the first program and the second program are running such that the second program operates on the same user input as the first program, the second program having an application program that is a replica of an application program of the first program, the program replication data causing the second program to mirror a state of the first program for enabling at least one of a user and an application interaction with the second program as if it were the first program when the first program fails, thereby improving efficiency of the system by reducing an amount of system downtime following a failure of the first program;

a first storage system configured to receive data storage requests from the first device; and

a second storage system, data stored in the first storage system being replicated in the second storage system.

24. A system having replicated programs and data storage, the system comprising:

a device configured to;

run a first program and a second program;

record, as program replication data, user input to the first program by monitoring the first program and trapping system calls;

send the program replication data to the second program when the first program and the second program are running such that the second program operates on the same user input as the first program, the second program having an application program that is a replica of an application program of the first program, the program replication data causing the second program to mirror a state of the first program for enabling at least one of a user and an application interaction with the second program as if it were the first program when the first program fails; and

use a record and reply program replication scheme to enable synchronization between the first and second programs, wherein using the record and reply program replication scheme reduces an amount of data involved with maintaining the synchronization;

a first storage system configured to receive data storage requests from the device; and

a second storage system, data stored in the first storage system being replicated in the second storage system.

25. A computer program product comprising a non-transitory computer useable medium having a computer readable program, wherein the computer readable program when executed on a computer causes the computer to:

record, by the computer and as program replication data, user input to a first program by monitoring the first program and trapping system calls;

send, by the computer, the program replication data from the first program to a second program such that the second program operates on the same user input as the first program, the second program having an application program that is a replica of an application program of the first program, the program replication data causing the second program to mirror a state of the first program for enabling at least one of a user and an application interaction with the second program as if it were the first program when the first program fails, thereby improving efficiency of the computer by reducing an amount of processing power and run time consumed by the computer in order to enable at least one of the user and the application interaction with the second program following a failure of the first program;

send, by the computer, data storage requests from the first program to a first storage system; and

replicate, by the computer, data stored in the first storage system in a second storage system.