DETECTION OF LOGICAL CORRUPTION IN PERSISTENT STORAGE AND AUTOMATIC RECOVERY THEREFROM

• US 20130055018A1
• Filed: 08/31/2011
• Published: 02/28/2013
• Est. Priority Date: 08/31/2011
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: JOSHI, Sameer, BAGAL, Prasad, WICKREMESINGHE, Rajiv, LONG, Richard, NANDYALA, Harish, HUANG, Shie-rei
• Granted Patent: US 8,732,521 B2
• Time in Patent Office: Days
• US Class Current: 714/19
• CPC Class Codes: G06F 11/008 Reliability or availability analysis
• CPC Class Codes: G06F 11/2058 using more than 2 mirrored copies
• CPC Class Codes: G06F 11/2064 while ensuring consistency
• CPC Class Codes: G06F 11/2082 Data synchronisation
• CPC Class Codes: G06F 11/3466 Performance evaluation by tracing or monitoring
• CPC Class Codes: G06F 2201/81 Threshold
• CPC Class Codes: G11B 20/1816 Testing
• CPC Class Codes: G11B 20/1883 Methods for assignment of alternate areas for defective areas

Abstract

A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Claims

1. A computer implemented method for restoring a block of data stored at a corrupted data site using two or more mirror sites within a disk group, the method comprising:

receiving, at a server, a trigger event from a component within an application server environment the trigger event indicating at least one corrupted block using a block identifier;

classifying the trigger event into at least one of a plurality of trigger event types;

retrieving, from at least two mirror sites, a first stored data block corresponding to the block identifier from a first mirror site, and a second stored data block corresponding to the block identifier from a second mirror site;

comparing the first stored data block to the second stored data block to determine a match value; and

writing, to the corrupted data site, the first stored data block when the match value is greater than a confidence threshold.

2. The method of claim 1, further comprising performing a logical consistency check on at least of portion of blocks in physical proximity to the corrupted data site.

3. The method of claim 1, further comprising performing a logical consistency check on at least of portion of blocks in logical proximity to the corrupted data site.

4. The method of claim 1, wherein the trigger event is raised by an application server.

5. The method of claim 1, wherein the trigger event is raised by a volume manager server.

6. The method of claim 1, wherein the classifying comprises classification into at least one of, a physical metadata trigger event, a virtual metadata trigger event, and an application data trigger event.

7. The method of claim 1, wherein the comparing comprises an exact byte-for-byte comparison.

8. The method of claim 1, wherein the comparing comprises a comparison of only the logical contents of the first stored data block to the logical contents of the second stored data block.

9. The method of claim 2, wherein performing a logical consistency check comprises one or more scan passes to identify additional or physical or logical corruptions.

10. The method of claim 2, wherein performing a logical consistency check comprises marking a block to signal subsequent online operations to explicitly resynchronize the marked block.

11. A computer system to restore a block of data stored at a corrupted data site using two or more mirror sites within a disk group, comprising:

a computer processor to execute a set of program code instructions; and

a memory to hold the program code instructions, in which the program code instructions comprises program code,

to perform receiving a trigger event from a component within an application server environment the trigger event indicating at least one corrupted block using a block identifier;

to perform classifying the trigger event into at least one of a plurality of trigger event types;

to perform retrieving, from at least two mirror sites, a first stored data block corresponding to the block identifier from a first mirror site, and a second stored data block corresponding to the block identifier from a second mirror site;

to perform comparing the first stored data block to the second stored data block to determine a match value; and

to perform writing, to the corrupted data site, the first stored data block when the match value is greater than a confidence threshold.

12. The computer system of claim 11, further comprising program code to perform a logical consistency check on at least of portion of blocks in physical proximity to the corrupted data site.

13. The computer system of claim 11, further comprising program code to perform a logical consistency check on at least of portion of blocks in logical proximity to the corrupted data site.

14. The computer system of claim 11, wherein the trigger event is raised by an application server.

15. The computer system of claim 11, wherein the trigger event is raised by a volume manager server.

16. The computer system of claim 11, wherein the classifying comprises classification into at least one of, a physical metadata trigger event, a virtual metadata trigger event, and an application data trigger event.

17. The computer system of claim 11, wherein the comparing comprises an exact byte-for-byte comparison.

18. The computer system of claim 11, wherein the comparing comprises a comparison of only the logical contents of the first stored data block to the logical contents of the second stored data block.

19. A computer program product embodied in a non-transitory computer readable medium, the computer readable medium having stored thereon a sequence of instructions which, when executed by a processor causes the processor to execute a method to implement restoring a block of data stored at a corrupted data site using two or more mirror sites within a disk group, the method comprising:

receiving, at a server, a trigger event from a component within an application server environment the trigger event indicating at least one corrupted block using a block identifier;

classifying the trigger event into at least one of a plurality of trigger event types;

retrieving, from at least two mirror sites, a first stored data block corresponding to the block identifier from a first mirror site, and a second stored data block corresponding to the block identifier from a second mirror site;

comparing the first stored data block to the second stored data block to determine a match value; and

writing, to the corrupted data site, the first stored data block when the match value is greater than a confidence threshold.

20. The computer program product of claim 19, further comprising performing a logical consistency check on at least of portion of blocks in physical proximity to the corrupted data site.