In-memory caching with on-demand migration

• US 9,619,391 B2
• Filed: 05/28/2015
• Issued: 04/11/2017
• Est. Priority Date: 05/28/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Agarwal, Kanak B.
• Primary Examiner(s): TSUI, DANIEL D
• Application Number:
  US14/724,068
• Publication Number:
  US 20160350226A1
• Time in Patent Office: 684 Days
• Field of Search: None
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 12/0842 for multiprocessing or multitasking
• CPC Class Codes: G06F 12/0864 using pseudo-associative means, e.g. set-associative or hashing
• CPC Class Codes: G06F 12/0868 Data transfer between cache memory and other subsystems, e.g. storage devices or host systems
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/314 In storage network, e.g. network attached cache
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

For on-demand migration of data in a distributed memory storage configuration, an identifier is transformed at a client into a transformed identifier. From a current configuration of a first plurality of servers operating on a server-side at a current time, a current server is identified at the client. From a previous configuration of a second plurality of servers operating on a server-side at a previous time, a previous server is identified at the client. A first request is sent to the current server to perform an operation using the identifier. A second request is sent to the previous server to perform the operation using the identifier. When a first data in response to the first request is invalid and a second data in response to the second request is valid, the second data is migrated to the current server in a migration request from the client to the current server.

Claims

1. A method for on-demand migration of data in a distributed memory storage configuration, the method comprising:

transforming, at a client-side data processing system, using a processor, a first identifier to form a transformed identifier;

identifying, at the client-side data processing system, from a current configuration of a first plurality of servers operating on a server-side at a current time, a current server;

identifying, at the client-side data processing system, from a previous configuration of a second plurality of servers operating on a server-side at a previous time, a previous server;

sending, a first request to the current server to perform an operation using the first identifier;

sending, a second request to the previous server to perform the operation using the first identifier; and

migrating, responsive to a first data in response to the first request being invalid and responsive to a second data in response to the second request being valid, the second data in a migration request from the client side data processing system to the current server.

2. The method of claim 1, further comprising:

saving, at the client-side data processing system, the current configuration of the first plurality of servers at the current time; and

designating at the current time, an already saved configuration of the second plurality of servers operating on a server-side at the previous time, as the previous configuration.

3. The method of claim 1, further comprising:

receiving, at the client-side data processing system, a write request to perform a write operation on the server-side with a third data corresponding to a second identifier;

sending a third request to the current server to perform the write operation; and

sending a fourth request to the previous server to perform a delete operation corresponding to the second identifier.

4. The method of claim 3, further comprising:

sending a fifth request to a second previous server to perform a second delete operation corresponding to the second identifier.

5. The method of claim 1, further comprising:

receiving the first request from a requestor application executing on the client-side data processing system, wherein the first request includes the first identifier, wherein the first identifier corresponds to a data object stored on a server-side data processing system; and

sending the second data to the requestor application in response to the first request.

6. The method of claim 1, further comprising:

invalidating the second data in the previous server by sending a delete request from the client side data processing system to the previous server.

7. The method of claim 1, further comprising:

receiving the first data in a first response from the current server; and

receiving the second data in a second response from the previous server, wherein the previous server is not designated in the current configuration to process the operation.

8. The method of claim 1, wherein the first data being invalid comprises the first data being unavailable from the current server.

9. The method of claim 1, wherein each server in the first plurality of servers is a memcache server, and wherein the current configuration is a ring of memcache servers.

10. The method of claim 1, further comprising:

determining, as a part of the identifying the current server, that the current server is designated in the current configuration to process the operation; and

determining, as a part of the identifying the previous server, that the previous server was designated in the previous configuration to process the operation.

11. The method of claim 1, wherein the transforming comprises hashing, and wherein the transformed identifier is a hash value of the first identifier according to a hashing algorithm.

12. The method of claim 1, further comprising:

determining that the current server was added to the previous configuration after the previous time.

13. A computer usable program product comprising a computer readable storage device including computer usable code for on-demand migration of data in a distributed memory storage configuration, the computer usable code comprising:

computer usable code for transforming, at a client-side data processing system, using a processor, a first identifier to form a transformed identifier;

computer usable code for identifying, at the client-side data processing system, from a current configuration of a first plurality of servers operating on a server-side at a current time, a current server;

computer usable code for identifying, at the client-side data processing system, from a previous configuration of a second plurality of servers operating on a server-side at a previous time, a previous server;

computer usable code for sending, a first request to the current server to perform an operation using the first identifier;

computer usable code for sending, a second request to the previous server to perform the operation using the first identifier; and

computer usable code for migrating, responsive to a first data in response to the first request being invalid and responsive to a second data in response to the second request being valid, the second data in a migration request from the client side data processing system to the current server.

14. The computer usable program product of claim 13, further comprising:

computer usable code for saving, at the client-side data processing system, the current configuration of the first plurality of servers at the current time; and

computer usable code for designating at the current time, an already saved configuration of the second plurality of servers operating on a server-side at the previous time, as the previous configuration.

15. The computer usable program product of claim 13, further comprising:

computer usable code for receiving, at the client-side data processing system, a write request to perform a write operation on the server-side with a third data corresponding to a second identifier;

sending a third request to the current server to perform the write operation; and

computer usable code for sending a fourth request to the previous server to perform a delete operation corresponding to the second identifier.

16. The computer usable program product of claim 15, further comprising:

computer usable code for sending a fifth request to a second previous server to perform a second delete operation corresponding to the second identifier.

17. The computer usable program product of claim 13, further comprising:

computer usable code for receiving the first request from a requestor application executing on the client-side data processing system, wherein the first request includes the first identifier, wherein the first identifier corresponds to a data object stored on a server-side data processing system; and

computer usable code for sending the second data to the requestor application in response to the first request.

18. The computer usable program product of claim 13, wherein the computer usable code is stored in a computer readable storage device in a data processing system, and wherein the computer usable code is transferred over a network from a remote data processing system.

19. The computer usable program product of claim 13, wherein the computer usable code is stored in a computer readable storage device in a server data processing system, and wherein the computer usable code is downloaded over a network to a remote data processing system for use in a computer readable storage device associated with the remote data processing system.

20. A data processing system for on-demand migration of data in a distributed memory storage configuration, the data processing system comprising:

a storage device, wherein the storage device stores computer usable program code; and

a processor, wherein the processor executes the computer usable program code, and wherein the computer usable program code comprises;

computer usable code for transforming, at a client-side data processing system, using a processor, a first identifier to form a transformed identifier;

computer usable code for identifying, at the client-side data processing system, from a current configuration of a first plurality of servers operating on a server-side at a current time, a current server;

computer usable code for identifying, at the client-side data processing system, from a previous configuration of a second plurality of servers operating on a server-side at a previous time, a previous server;

computer usable code for sending, a first request to the current server to perform an operation using the first identifier;

computer usable code for sending, a second request to the previous server to perform the operation using the first identifier; and

computer usable code for migrating, responsive to a first data in response to the first request being invalid and responsive to a second data in response to the second request being valid, the second data in a migration request from the client side data processing system to the current server.