Restoring data segments of rolled-back transactions in a clustered file system

• US 8,489,655 B2
• Filed: 08/06/2012
• Issued: 07/16/2013
• Est. Priority Date: 08/25/2008
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Aronovich, Lior, Toaff, Yair, Paz, Gil, Asher, Ron
• Primary Examiner(s): Casanova, Jorge A
• Application Number:
  US13/567,240
• Publication Number:
  US 20120303592A1
• Time in Patent Office: 344 Days
• Field of Search: 707/812, 707/826
• US Class Current: 707/826
• CPC Class Codes: G06F 12/0802 Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
• CPC Class Codes: G06F 12/0815 Cache consistency protocols
• CPC Class Codes: G06F 12/0828 with concurrent directory accessing, i.e. handling multiple concurrent coherency transactions
• CPC Class Codes: G06F 12/084 with a shared cache
• CPC Class Codes: G06F 16/11 File system administration, e.g. details of archiving or snapshots file system backup G06F11/14
• CPC Class Codes: G06F 16/13 File access structures, e.g. distributed indices arrangements of input from, or output to, record carriers G06F3/06
• CPC Class Codes: G06F 16/16 File or folder operations, e.g. details of user interfaces specifically adapted to file systems
• CPC Class Codes: G06F 16/172 Caching, prefetching or hoarding of files
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 16/183 Provision of network file services by network file servers, e.g. by using NFS, CIFS network file access protocols H04L67/1097
• CPC Class Codes: G06F 16/1865 Transactional file systems
• CPC Class Codes: G06F 16/24552 Database cache management
• CPC Class Codes: G06F 21/6218 to a system of files or objects, e.g. local or distributed file system or database
• CPC Class Codes: G06F 2212/604 Details relating to cache allocation

Abstract

Systems, Methods, and Computer Program Products are provided for restoring data segments in a clustered file system (CFS). Contents of the data segments, that were modified during a transaction, which is being rolled-back to the most recent contents of the data segments prior to the transaction commencing, are restored. Locations of the most recent contents of the data segments, which are restored, are identified.

Claims

1. A method for restoring data segments of a rolled-back transaction in a clustered file system (CFS) using a processor device, the method comprising:

restoring, in a cache, contents of the data segments that were modified during a transaction which is being rolled-back, to most recent contents of the data segments prior to the transaction commencing; and

identifying locations of the most recent contents of the data segments that are restored, including, for the data segments modified during the transaction, identifying a location of the most recent contents of the data segments prior to the transaction commencing;

wherein;

if the data segments were marked as modified in the cache at the time the data segments were inserted into a list of data segments;

determining the data segments to be a first type where the most recent contents of the data segments appear only in a transaction journal, and

if the data segments are not marked as modified in the cache at the time the data segments were inserted into the list of data segments;

determining the data segments to be a second type where the most recent contents of the data segments appear only in a final storage location.

2. The method of claim 1, further including scanning a list of data segments modified within the transaction being rolled-backed.

3. The method of claim 1, further including recording for each of the data segments whether the most recent contents is one of the first type and the second type in the list of data segments.

4. The method of claim 3, further including discarding from the cache the data segments determined to be the second type.

5. The method of claim 1, further including, for the data segments determined to be the first type, restoring the most recent contents of the data segments from the transaction journal into the cache and setting a modification indication as positive thereby enabling restored data segments to be written to the final storage location.

6. The method of claim 5, further including scanning the transaction journal from an ending to a beginning of the transaction journal and considering only first occurrences of the data segments of the first type in the transaction journal.

7. A system for restoring data segments of a rolled-back transaction in a clustered file system (CFS), the system comprising:

a cluster of nodes,

the CFS including the cluster of nodes forming a computer cluster,

a distributed shared memory (DSM) agent within a node of the cluster of nodes;

a plurality of storage devices in communication with the CFS,

a cache associated with the node,

a transaction journal associated with the CFS, and

a processor device having a memory coupled to the processor device for controlling the CFS, wherein the processor device is assigned to the node and the node is in communication with the plurality of storage devices, wherein the processor device;

restores, in a cache, contents of the data segments that were modified during a transaction which is being rolled-back, to most recent contents of the data segments prior to the transaction commencing, and

identifies locations of the most recent contents of the data segments that are restored, including, for the data segments modified during the transaction, identifying a location of the most recent contents of the data segments prior to the transaction commencing;

wherein;

if the data segments were marked as modified in the cache at the time the data segments were inserted into a list of data segments;

determining the data segments to be a first type where the most recent contents of the data segments appear only in a transaction journal, and

if the data segments are not marked as modified in the cache at the time the data segments were inserted into the list of data segments;

determining the data segments to be a second type where the most recent contents of the data segments appear only in a final storage location.

8. The system of claim 7, wherein the processor device scans a list of data segments modified within the transaction being rolled-backed.

9. The system of claim 7, wherein the processor device records for each of the data segments whether the most recent contents is one of the first type and the second type in the list of data segments.

10. The system of claim 9, wherein the processor device discards from the cache the data segments determined to be the second type.

11. The system of claim 7, wherein the processor device, for the data segments determined to be the first type, restores the most recent contents of the data segments from the transaction journal into the cache and setting a modification indication as positive thereby enabling restored data segments to be written to the final storage location.

12. The system of claim 11, wherein the processor device scans the transaction journal from an ending to a beginning of the transaction journal and considering only first occurrences of the data segments of the first type in the transaction journal.

13. A computer program product for restoring data segments of a rolled-back transaction in a clustered file system (CFS) using a processor device, the computer program product comprising a non-transitory computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:

a first executable portion that restores, in a cache, contents of the data segments that were modified during a transaction which is being rolled-back, to most recent contents of the data segments prior to the transaction commencing, and

a second executable portion that identifies locations of the most recent contents of the data segments that are restored, including, for the data segments modified during the transaction, identifying a location of the most recent contents of the data segments prior to the transaction commencing;

wherein;

if the data segments were marked as modified in the cache at the time the data segments were inserted into a list of data segments;

determining the data segments to be a first type where the most recent contents of the data segments appear only in a transaction journal, and

if the data segments are not marked as modified in the cache at the time the data segments were inserted into the list of data segments;

determining the data segments to be a second type where the most recent contents of the data segments appear only in a final storage location.

14. The computer program product of claim 13, further including a third executable portion that scans a list of data segments modified within the transaction being rolled-backed.

15. The computer program product of claim 13, further including a third executable portion that records for each of the data segments whether the most recent contents is one of the first type and the second type in the list of data segments.

16. The computer program product of claim 15, further including a fourth executable portion that discards from the cache the data segments determined to be the second type.

17. The computer program product of claim 13, further including a third executable portion that, for the data segments determined to be the first type, restores the most recent contents of the data segments from the transaction journal into the cache and setting a modification indication as positive thereby enabling restored data segments to be written to the final storage location.

18. The computer program product of claim 17, further including a fourth executable portion that scans the transaction journal from an ending to a beginning of the transaction journal and considering only first occurrences of the data segments of the first type in the transaction journal.