Method for identifying the time at which data was written to a data store

• US 7,725,667 B2
• Filed: 03/12/2004
• Issued: 05/25/2010
• Est. Priority Date: 09/23/2003
• Status: Expired due to Fees

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Operating Corporation (Gen Digital Inc.)
• Inventors: Rowan, Michael T., Rodgers, Kevin F.
• Primary Examiner(s): Bragdon; Reginald G
• Assistant Examiner(s): Gu; Shawn X
• Application Number:
  US10/799,428
• Publication Number:
  US 20050063374A1
• Time in Patent Office: 2,265 Days
• Field of Search: None
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery

Abstract

A method for identifying a time at which first data was written to a data store. A data store is configured to respond to data requests made to the data store with the data in the data store at a first time in the past. The method can be used to identify a time, for example, at which a data store was corrupted.

Claims

1. A method for identifying a time at which first data was written to a first data store, comprising the steps of:

configuring a second data store to respond to data requests with first data if the first data was stored in the first data store at a first time in the past;

requesting second data from the second data store;

receiving the second data;

determining from the second data if the first data store contained the first data at the first time by comparing the second data and the first data; and

identifying a second time, different from the first time, if the first data store did not contain the first data at the first time.

2. The method of claim 1, further comprising the steps of:

configuring the second data store to respond to data requests made to the second data store with data stored in the first data store at the second time in the past;

requesting third data from the second data store;

receiving the third data from the second data store; and

determining from the third data if the first data store contained the first data at the second time.

3. The method of claim 1, further comprising the steps of:

configuring the second data store to respond to data requests made to the second data store with data stored in the first data store at a third time in the past;

requesting fourth data from the second data store;

receiving the fourth data from the second data store; and

determining from the fourth data if the first data store contained the first data at the third time.

4. The method of claim 3 wherein the second time and the third time are selected in response to at least one previously completed determining step.

5. The method of claim 1 wherein the first data is corrupted data.

6. The method of claim 1 wherein the first data store is located on a same logical device as the second data store.

7. The method of claim 1 wherein the configuring step further comprises communicating the first time to the second data store.

8. The method of claim 7 wherein the configuring step further comprises communicating the first time to the second data store via a channel which is used to communicate the request for second data.

9. The method of claim 7 wherein the configuring step further comprises communicating the first time to the second data store via a different channel than a channel used to communicate the request for second data.

10. The method of claim 1 wherein the second data store is a virtual representation of the first data store at the first time.

11. The method of claim 1, further comprising, prior to the configuring step, continuously saving information stored in the first data store before it is overwritten.

12. The method of claim 1, wherein the first time is a time selected from a substantially continuous time interval between a past time and a current time.

13. The method of claim 1 wherein the second data store is configured using a user interface.

14. The method of claim 1 wherein the second data store is configured by an I/O command.

15. The method of claim 1 wherein the second data store is configured substantially immediately.

16. The method of claim 15 wherein the second data store is configured substantially immediately relative to at least one time at which the first data was written to the first data store.

17. The method of claim 1 wherein the second data store is configured without copying data from the first data store to the second data store.

18. A method for identifying a time at which a data store was corrupted, comprising the steps of:

(a) configuring the data store to respond to data requests with data if the data was present in the data store at a first time in the past;

(b) requesting data from the data store;

(c) receiving data from the data store in response to the request for data from the data store; and

(d) determining from the received data whether the data store was corrupted at the first time;

(e) repeating steps (a), (b), (c), and (d) by substituting a second time for the first time, wherein the second time is earlier than the first time if it was determined that the data store was corrupted at the first time, and the second time is later than the first time if it was determined that the data store was not corrupted at the first time.

19. The method of claim 18 wherein step (e) comprises repeating steps (a), (b), (c), and (d) a number of repetitions, each repetition substituting a different respective time that was not employed in a previous repetition.

20. The method of claim 19, wherein the repeating step is performed until a time range in which the data store was corrupted is identified.

21. The method of claim 18, further comprising the step of configuring the data store to respond to data requests made to the data store with the data present in the data store during an identified time range.

22. A method for identifying a time at which a data store was modified in a predetermined manner, comprising the steps of:

(a) configuring the data store to respond to data requests with data if the data was present in the data store at a first time in the past;

(b) requesting data from the data store;

(c) receiving data from the data store in response to the request of data from the data store; and

(d) determining from the received data whether the data store was modified in a predetermined manner at the first time;

(e) repeating steps (a), (b), (c), and (d) by substituting a second time for the first time, wherein the second time is earlier than the first time if it was determined that the data store was modified in the predetermined manner at the first time, and the second time is later than the first time if it was determined that the data store was not modified in the predetermined manner at the first time.

23. The method of claim 22, wherein step (e) comprises repeating steps (a), (b), (c), and (d) a number of repetitions, each repetition substituting a different respective time that was not employed in a previous repetition.

24. The method of claim 23, wherein the repeating step is performed until a time range in which the data store was modified in the predetermined manner is identified.

25. The method of claim 22, further comprising the step of configuring the data store to respond to data requests made to the data store with data present in the data store during an identified time range.