Data integrity and parity consistency verification

1. A method comprising:

retrieving, by a storage server, a row parity algebraic signature and a diagonal parity algebraic signature for each of: one or more data blocks, a row parity block and a diagonal parity block;

logically combining the row parity algebraic signatures of the one or more data blocks to generate a first result;

comparing the first result to the retrieved row parity algebraic signature for the row parity block;

aligning a plurality of sub-chunks of the one or more data blocks, the row parity block and the diagonal parity block in a stripe across a plurality of mass storage devices, and circularly shifting the sub-chunks such that sub-chunks corresponding to a diagonal parity set are located at a same offset from a start of their block;

logically combining the diagonal parity algebraic signatures of the one or more data blocks and the row parity block to generate a second result;

comparing the second result to the retrieved diagonal parity algebraic signature for the diagonal parity block; and

verifying data integrity and parity consistency for data in the one or more data blocks, row parity block and diagonal parity block if the first result matches the row parity algebraic signature and the second result matches the diagonal parity algebraic signature.

2. The method of claim 1 , further comprising:

computing the row parity algebraic signature for the one or more data blocks and the row parity block.

3. The method of claim 2 , wherein computing the row parity algebraic signature comprises applying a row parity algebraic signature function to data in each block.

4. The method of claim 1 , further comprising:

computing the diagonal parity algebraic signature torr the one or more data blocks, the row parity block and the diagonal parity block.

5. The method of claim 4 , wherein computing the diagonal parity algebraic signature comprises applying a diagonal parity algebraic signature function to data in each block.

6. The method of claim 1 , wherein logically combining the algebraic signatures comprises applying an exclusive-or (XOR) function to the algebraic signatures.

7. The method of claim 1 , further comprising:

comparing the algebraic signatures for each block with corresponding algebraic signatures stored within a checksum area of each block.

8. A system comprising:

an array of mass storage devices;

a signature encoder, coupled to the array of mass storage devices, and configured to:

compute a row parity algebraic signature for one or more data blocks and a row parity block;

compute a diagonal parity algebraic signature for the one or more data blocks, the row parity block and a diagonal parity block, wherein computing the diagonal parity algebraic signature comprises aligning a plurality of sub-chunks of the one or more data blocks, the row parity block and the diagonal parity block in a stripe across a plurality of mass storage devices, and circularly shifting the sub-chunks such that sub-chunks corresponding to a diagonal parity set are located at a same offset from a start of their block; and

a storage server, coupled to the array of mass storage devices, and configured to:

retrieve the row parity algebraic signature and the diagonal parity algebraic signature for the one or more data blocks, the row parity block and the diagonal parity block;

logically combine the row parity algebraic signatures of the one or more data blocks to generate a first result;

compare the first result to the retrieved row parity algebraic signature for the row parity block;

logically combine the diagonal parity algebraic signatures of the one or more data blocks and the row parity block to generate a second result;

compare the second result to the retrieved diagonal parity algebraic signature for the diagonal parity block; and

verify data integrity and parity consistency for data in the one or more data blocks, row parity block and diagonal parity block if the first result matches the row parity algebraic signature and the second result matches the diagonal parity algebraic signature.

9. The system of claim 8 , wherein computing the row parity algebraic signature comprises applying a row parity algebraic signature function to data in each block.

10. The system of claim 8 , wherein computing the diagonal parity algebraic signature comprises applying a diagonal parity algebraic signature function to data in each block.

11. The system of claim 8 , wherein logically combining the algebraic signatures comprises applying an exclusive-or (XOR) function to the algebraic signatures.

12. The system of claim 8 , wherein the storage server is further configured to compare the algebraic signatures for each block with corresponding algebraic signatures stored within a checksum area of each block.

13. The system of claim 8 , wherein the signature encoder comprises a dongle.

14. The system of claim 8 , herein the signature encoder comprises a shelf controller.

15. A storage server comprising:

a processor unit; and

a memory, coupled to the processor unit, storing instructions which, when executed by the processor unit, cause the system to:

retrieve a row parity algebraic signature and a diagonal parity algebraic signature for one or more data blocks, a row parity block and a diagonal parity block;

logically combine the row parity algebraic signatures of the one or more data blocks to generate a first result;

compare the first result to the retrieved row parity algebraic signature for the row parity block;

align a plurality of sub-chunks of the one or more data blocks, the row parity block and the diagonal parity block in a stripe across a plurality of mass storage devices, wherein aligning the plurality of sub-chunks comprises circularly shifting the sub-chunks such that sub-chunks corresponding to a diagonal parity set are located at a same offset from a start of their block;

logically combine the diagonal panty algebraic signatures of the one or more data blocks and the row parity block to generate a second result;

compare the second result to the retrieved diagonal parity algebraic signature for the diagonal parity block; and

verify data integrity and parity consistency for data in the one or more data blocks, row parity block and diagonal parity block if the first result matches the row parity algebraic signature and the second result matches the diagonal parity algebraic signature.

16. The storage server of claim 15 , wherein logically combining the algebraic signatures comprises applying an exclusive-or (XOR) function to the algebraic signatures.

17. A method comprising:

computing, by a signature encoder, a row parity algebraic signature;

computing, by the signature encoder, a diagonal parity algebraic signature for a data block in a mass storage array, wherein the computing the diagonal parity algebraic signature comprises aligning a plurality of sub-chunks of one or more data blocks, a row parity block and a diagonal parity block in a stripe across a plurality of mass storage devices, and circularly shifting the sub-chunks such that sub-chunks corresponding to a diagonal parity set are located at a same offset from a start of their block;

sending the row parity algebraic signature and the diagonal parity algebraic signature to a storage server; and

verifying data integrity and parity consistency of the data block using the row parity algebraic signature and the diagonal parity algebraic signature.

18. The method of claim 17 , wherein verifying data integrity and parity consistency comprises:

logically combining the row parity algebraic signature with row parity algebraic signatures of one or more other data blocks to generate a first result;

comparing the first result to a row parity algebraic signature for a row parity block;

logically combining the diagonal parity algebraic signature with diagonal parity algebraic signatures of the one or more other data blocks and the row parity block to generate a second result; and

comparing the second result to a diagonal parity algebraic signature for the diagonal parity block.

19. The method of claim 17 , further comprising:

determining that the data integrity and parity consistency are valid if the first result matches the row parity algebraic signature for the row parity block and the second result matches the diagonal parity algebraic signature for the diagonal parity block.