End-to-end disk data checksumming

• US 20030023933A1
• Filed: 07/27/2001
• Published: 01/30/2003
• Est. Priority Date: 07/27/2001
• Status: Abandoned Application

• Current Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Duncan, William L.
• Application Number:
  US09/917,315
• Publication Number:
  US 20030023933A1
• Time in Patent Office: Days
• US Class Current: 714/807
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G11B 20/18 Error detection or correction; Testing , e.g. of drop-outs
• CPC Class Codes: G11B 20/1803 by redundancy in data representation
• CPC Class Codes: H03M 13/09 Error detection only, e.g. using cyclic redundancy check [CRC] codes or single parity bit

Abstract

Provided is a method, system, and an article of manufacture for implementing a checksumming technique to a device driver to detect silent data corruption during read requests. A storage device is reformatted to create larger data blocks where a checksum can be stored with the data. A checksum is added during a write request, and calculated and compared during a read request. If an error was detected during retrieval, an error message is generated. However, if no error is detected, the checksum is removed before returning the data blocks to the application program.

Claims

1. A method for implementing an error detection scheme to read/write requests generated by an application program in a host system to a storage device, comprising:

receiving with a driver program in the host system a write request from the application program to write data blocks at a first size to target data blocks in the storage device, wherein the target data blocks in the storage device have a second size, wherein the second size is larger than the first size;

generating with the driver program a checksum for each data block in the write request;

transmitting with the driver program the data block with the checksum to the storage device, wherein the storage device stores the data blocks and checksums in the target data blocks.

2. The method of claim 1, wherein the driver program further performs:

receiving data blocks and the checksum for each data block from the storage device in response to a read request;

calculating a new checksum for each retrieved data block;

determining, for each retrieved data block, whether an error occurred by comparing the new checksum with the checksum retrieved from the storage device with the data block;

for each data block, if the error is determined, then generating an error message; and

for each data block, if no error is determined, then returning the data block to the application program without the checksum stored with the data block in the storage device.

3. The method of claim 1, wherein the driver program is included within a target driver.

4. The method of claim 1, wherein the checksum is comprised of a 32-bit Exclusive-Or logic.

5. The method of claim 1, wherein the step of generating the checksum further comprises:

seeding the checksum with a logical block number of the target data block in the storage device that stores the data block.

6. The method of claim 1, further comprising:

initializing the storage device by creating data blocks at the second size;

running a script program to write initial data in each data block of the storage device; and

generating a checksumming flag to indicate that the storage device is checksum enabled.

7. The method of claim 1, wherein the second size is 528-bytes and the first size is 512-bytes.

8. The method of claim 1, further comprising:

checking a checksumming flag to determine whether the checksum should be generated.

9. The method of claim 2, the device program further comprising:

checking a checksumming flag to determine whether the checksum should be calculated and compared; and

if the checksumming flag indicates that the storage device is checksum enabled, checking the data structures.

10. The method of claim 1, wherein a target driver transmits the write request to an adaptor driver to communicate to an output device.

11. The method of claim 1, wherein the storage device is a member of a set of storage devices comprising a Direct Access Storage Device (DASD), Just a Bunch of Disks (JBOD), a Redundant Array of Independent Disks (RAID), a tape library and an optical library.

12. A system for implementing an error detection scheme to read/write requests generated by an application program to a storage device, comprising:

means for receiving with a driver program a write request from the application program to write data blocks at a first size to target data blocks in the storage device, wherein the target data blocks in the storage device have a second size, wherein the second size is larger than the first size;

means for generating with the driver program a checksum for each data block in the write request;

means for transmitting with the driver program the data block with the checksum to the storage device, wherein the storage device stores the data blocks and checksums in the target data blocks.

13. The system of claim 12, wherein the driver program further comprises:

means for receiving data blocks and the checksum for each data block from the storage device in response to a read request;

means for calculating a new checksum for each retrieved data block;

means for determining, for each retrieved data block, whether an error occurred by comparing the new checksum with the checksum retrieved from the storage device with the data block;

for each data block, if the error is determined, then a means for generating an error message; and

for each data block, if no error is determined, then a means for returning the data block to the application program without the checksum stored with the data block in the storage device.

14. The system of claim 12, wherein the driver program is included within a target driver.

15. The system of claim 12, wherein the checksum is comprised of a 32-bit Exclusive-Or logic.

16. The system of claim 12, wherein the means for generating the checksum further comprises:

means for seeding the checksum with a logical block number of the target data block in the storage device that stores the data block.

17. The system of claim 12, further comprising:

means for initializing the storage device by creating data blocks at the second size;

means for running a script program to write initial data in each data block of the storage device; and

means for generating a checksumming flag to indicate that the storage device is checksum enabled

18. The system of claim 12, wherein the second size is 528-bytes and the first size is 512-bytes.

19. The system of claim 12, further comprising:

means for checking a checksumming flag to determine whether the checksum should be generated.

20. The system of claim 13, the device program further comprising:

means for checking a checksumming flag to determine whether the checksum should be calculated and compared; and

if the checksumming flag indicates that the storage device is checksum enabled, means for checking the data structures.

21. The system of claim 12, wherein a target driver transmits the write request to an adaptor driver to communicate to an output device.

22. The system of claim 12, wherein the storage device is a member of a set of storage devices comprising a Direct Access Storage Device (DASD), Just a Bunch of Disks (JBOD), a Redundant Array of Independent Disks (RAID), a tape library and an optical library.

23. An article of manufacture for implementing an error detection scheme to read/write requests generated by an application program to a storage device, comprising a computer usable media including at least one computer program embedded therein that is capable or causing at least one computer to perform:

receiving with a driver program a write request from the application program to write data blocks at a first size to target data blocks in the storage device, wherein the target data blocks in the storage device have a second size wherein the second size is larger than the first size;

generating with the driver program a checksum for each data block in the write request;

transmitting with the driver program the data block with the checksum to the storage device, wherein the storage device stores the data blocks and checksums in the target data blocks.

24. The article of manufacture of claim 23, wherein the driver program further performs:

receiving data blocks and the checksum for each data block from the storage device in response to a read request;

calculating a new checksum for each retrieved data block;

determining, for each retrieved data block, whether an error occurred by comparing the new checksum with the checksum retrieved from the storage device with the data block;

for each data block, if the error is determined, then generating an error message; and

for each data block, if no error is determined, then returning the data block to the application program without the checksum stored with the data block in the storage device.

25. The article of manufacture of claim 23, wherein the driver program is included within a target driver.

26. The article of manufacture of claim 23, wherein the checksum is comprised of a 32-bit Exclusive-Or logic.

27. The article of manufacture of claim 23, wherein the step of generating the checksum further comprises:

seeding the checksum with a logical block number of the target data block in the storage device that stores the data block.

28. The article of manufacture of claim 23, further performing:

initializing the storage device by creating data blocks at the second size;

running a script program to write initial data in each data block of the storage device; and

generating a checksumming flag to indicate that the storage device is checksum enabled.

29. The article of manufacture of claim 23, wherein the second size is 528 bytes and the first size is 512-bytes.

30. The article of manufacture of claim 23, further performing:

checking a checksumming flag to determine whether the checksum should be generated.

31. The article of manufacture of claim 24, the device program further performing:

checking a checksumming flag to determine whether the checksum should be calculated and compared; and

if the checksumming flag indicates that the storage device is checksum enabled, data structures are also checked.

32. The article of manufacture of claim 23, wherein a target driver transmits the write request to an adaptor driver to communicate to an output device.

33. The article of manufacture of claim 23, wherein the storage device is a member of a set of storage devices comprising a Direct Access Storage Device (DASD), Just a Bunch of Disks (JBOD), a Redundant Array of Independent Disks (RAID), a tape library and an optical library.