Systems and methods for providing a modification history for a location within a data store

• US 8,521,973 B2
• Filed: 09/28/2007
• Issued: 08/27/2013
• Est. Priority Date: 08/24/2004
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Operating Corporation (NortonLifeLock Inc.)
• Inventors: Rowan, Michael, Rogers, Kevin
• Primary Examiner(s): NGUYEN, THAN VINH
• Application Number:
  US11/864,144
• Publication Number:
  US 20090019459A1
• Time in Patent Office: 2,160 Days
• Field of Search: None
• US Class Current: 711/162
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: G06F 11/0751 Error or fault detection not based on redundancy power supply failures G06F1/30; network fault management H04L41/06
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1474 in transactions G06F16/20 takes precedence
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency ensuring consistency in mirrored systems G06F11/2064
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

A storage management device can receive a request for a modification history for a location within a data store, determine one or more times at which at least a portion of data stored at the location was modified, and transmit the one or more determined times.

Claims

1. A method for obtaining a modification history for a location within a data store for recreating an image of the data store at any previous point in time without reference to a snapshot of the data store, the method comprising:

identifying, in a data store, a location associated with a data corruption event by parsing a historical index listing modifications to the data store, wherein the historical index is a record of write operations separately maintained and consulted within the data store, wherein the location is an address range within the data store, wherein the address range comprises a logical block address (LBA) and a length, and wherein the logical block address specifies a beginning of the address range and the length specifies the length of the address range;

transmitting, by a computer, a request for a modification history for the identified location without reference to a snapshot of the data store, wherein the identified location is not associated with a previously created snapshot;

determining which of the listed modifications were made to data at an address range at least partially overlapping the identified location;

tracking times where modifications were made based on the address range at least partially overlapping the identified location; and

receiving, by the computer in response to the transmitted request, at least one time at which at least a portion of data stored at the identified location was modified without reference to a snapshot of the data store.

2. The method of claim 1, further comprising:

receiving, by the computer in response to the transmitted request, at least one address range within the data store at which at least a portion of data stored at the identified location was modified at the least one time.

3. The method of claim 1, wherein the listed modifications comprises at least one of a subset, an intersecting set, a superset, and a whole set of modified data.

4. A method for requesting a modification history for a location within a data store for recreating an image of the data store at any previous point in time without reference to a snapshot of the data store, the method comprising:

identifying, in a data store, a location associated with a data corruption event by parsing a historical index listing modifications to the data store, wherein the historical index is a record of write operations separately maintained and consulted within the data store;

determining an address range that corresponds to the identified location, wherein the identified location is not associated with a previously created snapshot, wherein the address range comprises a logical block address (LBA) and a length, and wherein the logical block address specifies a beginning of the address range and the length specifies the length of the address range;

generating a data packet containing the address range and an operation code requesting a modification history for the address range without reference to a snapshot of the data store, wherein the modification history comprises data having an address range at least partially overlapping the identified location and times where modifications were made to the data; and

transmitting the data packet to a storage management device coupled to the data store.

5. The method of claim 4, wherein the operation code requests at least one time at which at least a portion of data stored at the address range was modified.

6. The method of claim 4, further comprising:

receiving at least one time at which at least a portion of data stored at the identified location was modified.

7. The method of claim 4, wherein the modification history comprises at least one of a subset, an intersecting set, a superset, and a whole set of modified data.

8. A method for providing a modification history for a location within a data store for recreating an image of the data store at any previous point in time without reference to a snapshot of the data store, the method comprising:

receiving, by a storage management device, a request for a modification history for a location within a data store, wherein the location is not associated with a previously created snapshot without reference to a snapshot of the data store, wherein the location is an address range within the data store, wherein the address range comprises a logical block address (LBA) and a length, and wherein the logical block address specifies a beginning of the address range and the length specifies the length of the address range;

determining, by the storage management device, at least one time from which all data stored at the location was modified without reference to a snapshot of the data store by parsing a historical index listing modifications to the data store, wherein the historical index is a record of write operations separately maintained and consulted within the data store;

determining, by the computer, which modifications listed in the history index were made to data at an address range at least partially overlapping the identified location; and

transmitting, by the storage management device in response to the received request, the at least one determined time.

9. The method of claim 8, wherein at least one portion of the data stored at the location was modified at a different time from the at least one determined time.

10. The method of claim 8, further comprising:

transmitting, by the storage management device in response to the received request, at least one address range within the data store at which at least a portion of data stored at the location was modified at the least one determined time.

11. The method of claim 8, wherein modifications listed in the history index comprises at least one of a subset, an intersecting set, a superset, and a whole set of modified data.