Method and system for virtual on-demand recovery for real-time, continuous data protection

• US 8,151,140 B2
• Filed: 07/28/2010
• Issued: 04/03/2012
• Est. Priority Date: 07/20/2005
• Status: Active Grant

• Current Assignee: Quest Software, Inc.
• Original Assignee: Quest Software, Inc.
• Inventors: Sim-Tang, Siew Yong
• Primary Examiner(s): Baderman, Scott
• Assistant Examiner(s): PATEL, KAMINI B
• Application Number:
  US12/845,215
• Publication Number:
  US 20110185227A1
• Time in Patent Office: 615 Days
• Field of Search: 714/20
• US Class Current: 714/20
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• 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 data management system or “DMS” provides an automated, continuous, real-time, substantially no downtime data protection service to one or more data sources associated with a set of application host servers. To facilitate the data protection service, a host driver embedded in an application server captures real-time data transactions, preferably in the form of an event journal that is provided to other DMS components. The driver functions to translate traditional file/database/block I/O and the like into a continuous, application-aware, output data stream. The host driver includes an event processor. When an authorized user determines that a primary copy of the data in the host server has become incorrect or corrupted, the event processor can perform a recovery operation to an entire data source or a subset of the data source using former point-in-time data in the DMS. The recovery operation may have two phases. First, the structure of the host data in primary storage is recovered to the intended recovering point-in-time. Thereafter, the actual data itself is recovered. The event processor enables such data recovery in an on-demand manner, in that it allows recovery to happen simultaneously while an application accesses and updates the recovering data.

Claims

1. A method of data recovery as a data protection service is being provided in a first processing environment, where, in connection with the data protection service, data has been stored in a data store remote from the first processing environment, the method comprising:

initiating a data recovery operation upon a determination that given data in the first processing environment needs to be recovered because it is missing, incorrect or corrupted;

recovering the given data to a former point-in-time state as reflected in the data store, wherein the recovery comprises;

presenting a structure of the given data to an application associated with a data source so that, from a point-of-view of the application, the data source is recovered prior to fully synchronizing the data source; and

synchronizing the data source to the structure of the given data; and

enabling the application to continue accessing or updating the given data during the recovery.

2. The method as described in claim 1 wherein the application continues to access or update the given data by generating a continuous, application-aware data stream and transferring the data stream to the data store.

3. The method as described in claim 1 wherein presenting the structure of the given data generates, from information in the data store, a sorted data list that is used to generate the structure in the data source.

4. The method as described in claim 3 further comprising filtering access requests during presenting the structure of the given data.

5. The method as described in claim 4 wherein READ requests are filtered synchronously.

6. The method as described in claim 5 wherein a given READ request is served from the data source.

7. The method as described in claim 5 wherein a given READ request is failed.

8. The method as described in claim 3 further comprising filtering access requests as the given data is synchronized to its former point-in-time.

9. The method as described in claim 4 wherein WRITE requests are failed.

10. The method as described in claim 8 further comprising:

using the sorted data list to determine whether an access request is for data that has not been recovered; and

if the access request is for data that has not been recovered, promptly recovering the data requested.

11. The method as described in claim 10 further comprising marking, in the sorted data list, a given data item as recovered if an application-aware data stream provided to the data store comprises information associated with the given data item.

12. The method as described in claim 1 further comprising the re-initiating protection of the data source following completion of the recovering state.

13. A method of recovering a data source in a host at a first location with associated data history at a second location remote from the first location, comprising:

upon initiation of a data recovery of the data source or a subset thereof, adjusting a current state of the data source at the second location by moving a past state to the current state; and

retrieving a most current state from the second location;

recovering the data source or the subset thereof using the most current state retrieved from the second location, wherein the data source or the subset thereof remains accessible to an application in the host during the recovery; and

continuing collection of the data history at the second location as the data source or the subset thereof is recovered and following such recovery.

14. An apparatus for use in providing a data recovery service to a data source in a host, comprising:

a processor; and

code executable by the processor to continuously generate and forward to a remote location a data history; and

code executable by the processor and responsive to initiation of a data recovery operation for the data source or a subset thereof (a) to retrieve from the remote location a former point-in-time state of the data source or the subset thereof, and (b) to recover the data source or the subset thereof to the former point-in-time state,

wherein the recovery comprises;

presenting a structure of given data to an application associated with the data source so that, from a point-of-view of the application, the data source is recovered prior to fully synchronizing the data source;

synchronizing the data source to the structure of the given data; and

enabling the application to continue accessing or updating the given data during the recovery.

15. The apparatus as described in claim 14 further comprising code executable by the processor to recover a structure of the data source or the subset.

16. The apparatus as described in claim 14 further comprising an interface at which a recovery command is entered to initiate the data recovery operation.