Method and system for backing up data

• US 7,490,103 B2
• Filed: 02/04/2005
• Issued: 02/10/2009
• Est. Priority Date: 02/04/2004
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Chang, Yafen Peggy, Johnston, Craig Anthony, Trimmer, Donald Alvin, Stager, Roger Keith, Saxena, Pawan, Blaser, Rico
• Primary Examiner(s): AL HASHEMI, SANA A
• Application Number:
  US11/051,793
• Publication Number:
  US 20050216536A1
• Time in Patent Office: 1,467 Days
• Field of Search: 707/103.R, 707/101, 707/102, 707/104.1
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1466 to make the backup process non-disruptive
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• 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
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing

Abstract

A method and system for generating a snapshot in a consistent state is disclosed. The system comprises a host computer, a primary data storage, a data protection unit, and a secondary data storage. The data protection unit monitors a state of an application which is running on the host computer. The data protection unit generates a snapshot of data stored in a primary data storage when the application is in a consistent state, and stores the snapshot on a secondary storage. In the event of a system failure, the data is recovered using the last snapshot.

Claims

1. A system for backing up data, the system comprising:

a host computer configured to run an application, wherein the application generates data that is stored in a buffer of the host computer;

a primary data storage configured to store the data generated by the application, wherein the data is copied from the buffer of the host computer to the primary data storage upon the occurrence of a specific condition;

a data protection unit configured to monitor a state of the application and to generate a snapshot for the data stored in the primary data storage when the application is in a consistent state without suspending operation of the application to generate the snapshot, wherein the application generates state information to indicate the consistent state, and wherein the state information includes setting a specific bit to indicate to the data protection unit that the buffer has been flushed out to the primary data storage; and

a secondary data storage configured to store the snapshot.

2. The system of claim 1 wherein the primary data storage is directly connected to the host computer.

3. The system of claim 1 wherein the data protection unit controls both the primary data storage and the secondary data storage.

4. The system of claim 1 further comprising a switch for connecting the primary data storage and the data protection unit to the host computer.

15. The system of claim 1, wherein the consistent state exists when there is no pending data to be written from the buffer to the primary data storage.

16. The system of claim 1, wherein the data protection unit generates snapshots based on consistent states of a plurality of applications.

5. A system for backing up data, the system comprising:

a host computer configured to run an application, wherein the application generates data that is stored in a buffer of the host computer;

a primary data storage configured to store the data generated by the application, wherein the data is copied from the buffer of the host computer to the primary data storage upon the occurrence of a specific condition;

a data protection unit configured to;

generate a snapshot of the data stored in the primary data storage without suspending operation of the application to generate the snapshot;

determine when the application was in a consistent state, wherein the application generates state information to indicate the consistent state, and wherein the state information includes setting a specific bit to indicate to the data protection unit that the buffer has been flushed out to the primary data storage; and

locate a snapshot corresponding to a time when the application was in the consistent state; and

a secondary data storage configured to store the snapshot.

6. The system of claim 5 wherein the consistent state is determined by inspecting a log of write streams.

7. The system of claim 5 wherein the primary data storage is directly connected to the host computer.

8. The system of claim 5 wherein the data protection unit controls both the primary data storage and the secondary data storage.

9. The system of claim 5 further comprising a switch for connecting the primary data storage and the data protection unit to the host computer.

17. The system of claim 5, wherein the data protection unit generates snapshots based on consistent states of a plurality of applications.

10. A method for backing up data, comprising the steps of:

running an application on a host computer, wherein the application generates data that is stored in a buffer of the host computer;

storing the data generated by the application in a primary data storage, wherein the data is copied from the buffer of the host computer to the primary data storage upon the occurrence of a specific condition;

monitoring a state of the application to determine if the application is in a consistent state, wherein a consistent state exists when there is no data generated by the application waiting to be written to a primary data storage;

generating a snapshot for the data stored in the primary data storage when the application is in the consistent state without suspending operation of the application, wherein the application generates state information to indicate the consistent state, and wherein the state information includes setting a specific bit to indicate to the data protection unit that the buffer has been flushed out to the primary data storage; and

storing the snapshot in a secondary data storage.

11. The method according to claim 10, wherein if a system failure is detected, the method further comprising the step of:

recovering the system using the snapshot.

12. The method according to claim 10, wherein the monitoring step includes the application generating information to determine the state of the application.

13. The method according to claim 12, wherein the application generates an indicator of the state of the application.

14. The method according to claim 10, wherein the monitoring step includes analyzing a log of a journaling system associated with the application, wherein the application is in the consistent state a point in time when the log is empty at that point in time.

18. The method of claim 10, further comprising:

generating snapshots based on consistent states of a plurality of applications.