Detecting data integrity

• US 7,577,804 B2
• Filed: 10/06/2004
• Issued: 08/18/2009
• Est. Priority Date: 10/06/2004
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Jones, Michael John, Ripberger, Richard Anthony, Hsu, Yu-Cheng, Vageline, Michael P., Stelmach, Richard B.
• Primary Examiner(s): TSAI, SHENG JEN
• Application Number:
  US10/960,393
• Publication Number:
  US 20060075287A1
• Time in Patent Office: 1,777 Days
• Field of Search: 711/114, 711/162, 711/159, 714/6
• US Class Current: 711/159
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0683 Plurality of storage devices

Abstract

Provided are a method, system, and article of manufacture for detecting data integrity. An indicator is written to invalidate a data block that is capable of being stored in a plurality of sectors of a storage device, wherein the indicator is written to the storage device in at least one sector that is not included in the plurality of sectors. A writing of entire contents of the data block to the plurality of sectors of the storage device is initiated, in response to the writing of the indicator. The indicator is updated to validate the data block, in response to a completion of the writing of the entire contents of the data block to the plurality of sectors of the storage device.

Claims

1. A method, comprising:

writing an indicator to invalidate a data block that is capable of being stored in a plurality of sectors of a storage device, wherein the storage device is a disk based storage device, wherein the indicator is written to the storage device in at least one sector that is not included in the plurality of sectors;

initiating a writing of entire contents of the data block to the plurality of sectors of the storage device, in response to the writing of the indicator; and

updating the indicator to validate the data block, in response to a completion of the writing of the entire contents of the data block to the plurality of sectors of the storage device, wherein the at least one sector and the plurality of sectors are included in a same storage device, wherein a sector is a unit of data storage, wherein the at least one sector and the plurality of sectors comprise a record, wherein the at least one sector is a first sector of the record, wherein the indicator is a first indicator that is capable of validating the data block if at least one version of the entire contents of the data block has been completely written to the storage device, and wherein the first indicator has been written to the first sector, the method further comprising;

(i) writing a second indicator to the first sector, wherein the second indicator indicates a version number of the data block;

(ii) reading the first indicator and the second indicator written to the first sector; and

(iii) determining that the data block is valid and has the version number indicated in the second indicator, in response to determining that the first indicator has validated the data block, wherein the first sector comprises a record header, wherein the first indicator is a checkfield indicator comprising an error detection code, and wherein the second indicator is a generation count, and wherein the method further comprises;

(a) sending, by a storage controller, a plurality of versions of multi-sector data blocks and associated generation counts via a plurality of device adapters to a plurality of storage devices including a plurality of disk arrays;

(b) reading, by the storage controller, the plurality of versions of the multi-sector data blocks and the associated generation counts via the plurality of device adapters; and

(c) comparing, by the storage controller, generation counts of each of the plurality of versions of the multi-sector data blocks to determine one multi-sector data block with a most recent version of the data, wherein the plurality of versions of the multi-sector data blocks are maintained to assure data redundancy, and wherein in response to an interruption of data transfer before all sectors of a multi-sector data block have been written, the multi-sector data block and a last sector will not indicate the same generation count.

2. The method of claim 1, further comprising:

receiving an interruption subsequent to the initiating of the writing of the entire contents of the data block and prior to the updating of the indicator to validate the data block; and

reading the indicator to determine whether the data block is invalid.

3. The method of claim 1, wherein the indicator indicates a version number of the data block, the method further comprising:

writing a new version number of the data block with the entire contents of the data block in the plurality of sectors of the data block, wherein the updating of the indicator to validate the data block further comprises writing the new version number of the data block to the indicator.

4. The method of claim 1, the method further comprising:

reading version numbers corresponding to the data block and the indicator; and

determining that the data block is valid if the version numbers corresponding to the data block and the indicator are the same.

5. The method of claim 1, the method further comprising:

reading version numbers corresponding to the data block and the indicator; and

determining that the data block is invalid if the version numbers corresponding to the data block and the indicator are different.

6. The method of claim 1, further comprising:

storing a plurality of versions and associated version numbers of a plurality of data blocks in a plurality of storage devices; and

comparing the version numbers of the plurality of data blocks to determine one data block with most recently updated data.

7. The method of claim 6, wherein the plurality of storage devices are RAID arrays, wherein the writing, the initiating, the updating, the storing, and the comparing are performed by a storage controller that is coupled to the RAID arrays by the plurality of device adapters.

8. The method of claim 1, wherein the writing, the initiating, and the updating are performed by a data integrity controller implemented in a computational device coupled to the storage device.

9. The method of claim 1, wherein the writing, the initiating, and the updating are performed by a data integrity controller implemented in the storage device.

10. The method of claim 1, wherein the entire contents of the data block comprise data corresponding to the data block, wherein the data is generated by a computational device for storing in the storage device, and wherein the plurality of blocks in which the entire contents are stored in the storage does not include the indicator.

11. The method of claim 1, wherein the error detection code corresponds to a cyclic redundancy check of a corresponding multi-sector data block.

12. A system in communication with a storage device, the system comprising:

a memory; and

a processor coupled to the memory, wherein the processor performs operations, the operations comprising;

writing an indicator to invalidate a data block that is capable of being stored in a plurality of sectors of the storage device, wherein the storage device is a disk based storage device, wherein the indicator is written to the storage device in at least one sector that is not included in the plurality of sectors;

initiating a writing of entire contents of the data block to the plurality of sectors of the storage device, in response to the writing of the indicator; and

updating the indicator to validate the data block, in response to a completion of the writing of the entire contents of the data block to the plurality of sectors of the storage device, wherein the at least one sector and the plurality of sectors are included in a same storage device, wherein a sector is a unit of data storage, wherein the at least one sector and the plurality of sectors comprise a record, wherein the at least one sector is a first sector of the record, wherein the indicator is a first indicator that is capable of validating the data block if at least one version of the entire contents of the data block has been completely written to the storage device, and wherein the first indicator has been written to the first sector, the operations further comprising;

(i) writing a second indicator to the first sector, wherein the second indicator indicates a version number of the data block;

(ii) reading the first indicator and the second indicator written to the first sector; and

(iii) determining that the data block is valid and has the version number indicated in the second indicator, in response to determining that the first indicator has validated the data block, wherein the first sector comprises a record header, wherein the first indicator is a checkfield indicator comprising an error detection code, and wherein the second indicator is a generation count, and wherein the operations further comprise;

(a) sending, by a storage controller, a plurality of versions of multi-sector data blocks and associated generation counts via a plurality of device adapters to a plurality of storage devices including a plurality of disk arrays;

(b) reading, by the storage controller, the plurality of versions of the multi-sector data blocks and the associated generation counts via the plurality of device adapters; and

(c) comparing, by the storage controller, generation counts of each of the plurality of versions of the multi-sector data blocks to determine one multi-sector data block with a most recent version of the data, wherein the plurality of versions of the multi-sector data blocks are maintained to assure data redundancy, and wherein in response to an interruption of data transfer before all sectors of a multi-sector data block have been written, the multi-sector data block and a last sector will not indicate the same generation count.

13. The system of claim 12, the operations further comprising:

receiving an interruption subsequent to the initiating of the writing of the entire contents of the data block and prior to the updating of the indicator to validate the data block; and

reading the indicator to determine whether the data block is invalid.

14. The system of claim 12, wherein the indicator indicates a version number of the data block, the operations further comprising:

writing a new version number of the data block with the entire contents of the data block in the plurality of sectors of the data block, wherein the updating of the indicator to validate the data block further comprises writing the new version number of the data block to the indicator.

15. The system of claim 12, the operations further comprising:

reading version numbers corresponding to the data block and the indicator; and

determining that the data block is valid if the version numbers corresponding to the data block and the indicator are the same.

16. The system of claim 12, the operations further comprising:

reading version numbers corresponding to the data block and the indicator; and

determining that the data block is invalid if the version numbers corresponding to the data block and the indicator are different.

17. The system of claim 12, the operations further comprising:

storing a plurality of versions and associated version numbers of a plurality of data blocks in the plurality of storage devices; and

comparing the version numbers of the plurality of data blocks to determine one data block with most recently updated data.

18. The system of claim 17, wherein the plurality of storage devices are RAID arrays, wherein the writing, the initiating, the updating, the storing, and the comparing are performed by the storage controller that is coupled to the RAID arrays by the plurality of device adapters.

19. The system of claim 12, wherein the writing, the initiating, and the updating are performed by a data integrity controller implemented in a computational device coupled to the storage device.

20. The system of claim 12, wherein the writing, the initiating, and the updating are performed by a data integrity controller implemented in the storage device.

21. The system of claim 12, wherein the entire contents of the data block comprise data corresponding to the data block, wherein the data is generated by a computational device for storing in the storage device, and wherein the plurality of blocks in which the entire contents are stored does not include the indicator.

22. The system of claim 12, wherein the error detection code corresponds to a cyclic redundancy check of a corresponding multi-sector data block.

23. A computer readable storage medium, wherein code stored in the computer readable storage medium when executed by a processor causes operations, the operations comprising:

writing an indicator to invalidate a data block that is capable of being stored in a plurality of sectors of a storage device, wherein the storage device is a disk based storage device, wherein the indicator is written to the storage device in at least one sector that is not included in the plurality of sectors;

initiating a writing of entire contents of the data block to the plurality of sectors of the storage device, in response to the writing of the indicator; and

updating the indicator to validate the data block, in response to a completion of the writing of the entire contents of the data block to the plurality of sectors of the storage device, wherein the at least one sector and the plurality of sectors are included in a same storage device, wherein a sector is a unit of data storage, wherein the at least one sector and the plurality of sectors comprise a record, wherein the at least one sector is a first sector of the record, wherein the indicator is a first indicator that is capable of validating the data block if at least one version of the entire contents of the data block has been completely written to the storage device, and wherein the first indicator has been written to the first sector, the operations further comprising;

(i) writing a second indicator to the first sector, wherein the second indicator indicates a version number of the data block;

(ii) reading the first indicator and the second indicator written to the first sector; and

(iii) determining that the data block is valid and has the version number indicated in the second indicator, in response to determining that the first indicator has validated the data block, wherein the first sector comprises a record header, wherein the first indicator is a checkfield indicator comprising an error detection code, and wherein the second indicator is a generation count, and wherein the operations further comprise;

(a) sending, by a storage controller, a plurality of versions of multi-sector data blocks and associated generation counts via a plurality of device adapters to a plurality of storage devices including a plurality of disk arrays;

(b) reading, by the storage controller, the plurality of versions of the multi-sector data blocks and the associated generation counts via the plurality of device adapters; and

(c) comparing, by the storage controller, generation counts of each of the plurality of versions of the multi-sector data blocks to determine one multi-sector data block with a most recent version of the data, wherein the plurality of versions of the multi-sector data blocks are maintained to assure data redundancy, and wherein in response to an interruption of data transfer before all sectors of a multi-sector data block have been written, the multi-sector data block and a last sector will not indicate the same generation count.

24. The computer readable storage medium of claim 23, the operations further comprising:

receiving an interruption subsequent to the initiating of the writing of the entire contents of the data block and prior to the updating of the indicator to validate the data block; and

reading the indicator to determine whether the data block is invalid.

25. The computer readable storage medium of claim 23, wherein the indicator indicates a version number of the data block, the operations further comprising:

writing a new version number of the data block with the entire contents of the data block in the plurality of sectors of the data block, wherein the updating of the indicator to validate the data block further comprises writing the new version number of the data block to the indicator.

26. The computer readable storage medium of claim 23, the operations further comprising:

reading version numbers corresponding to the data block and the indicator; and

determining that the data block is valid if the version numbers corresponding to the data block and the indicator are the same.

27. The computer readable storage medium of claim 23, the operations further comprising:

reading version numbers corresponding to the data block and the indicator; and

determining that the data block is invalid if the version numbers corresponding to the data block and the indicator are different.

28. The computer readable storage medium of claim 23, the operations further comprising:

storing a plurality of versions and associated version numbers of a plurality of data blocks in the plurality of storage devices; and

comparing the version numbers of the plurality of data blocks to determine one data block with most recently updated data.

29. The computer readable storage medium of claim 28, wherein the plurality of storage devices are RAID arrays, wherein the writing, the initiating, the updating, the storing, and the comparing are performed by the storage controller that is coupled to the RAID arrays by the plurality of device adapters.

30. The computer readable storage medium of claim 23, wherein the writing, the initiating, and the updating are performed by a data integrity controller implemented in a computational device coupled to the storage device.

31. The computer readable storage medium of claim 23, wherein the writing, the initiating, and the updating are performed by a data integrity controller implemented in the storage device.

32. The computer readable storage medium of claim 23, wherein the entire contents of the data block comprise data corresponding to the data block, wherein the data is generated by a computational device for storing in the storage device, and wherein the plurality of blocks in which the entire contents are stored does not include the indicator.

33. The computer readable storage medium of claim 23, wherein the error detection code corresponds to a cyclic redundancy check of a corresponding multi-sector data block.