Application recovery in an information management system based on a pseudo-storage-device driver

• US 10,705,913 B2
• Filed: 11/10/2017
• Issued: 07/07/2020
• Est. Priority Date: 08/06/2014
• Status: Active Grant

• Current Assignee: CommVault Systems Incorporated
• Original Assignee: CommVault Systems Incorporated
• Inventors: Mitkar, Amit, Kumarasamy, Paramasivam
• Primary Examiner(s): Gurmu, Muluemebet
• Application Number:
  US15/809,776
• Publication Number:
  US 20180089031A1
• Time in Patent Office: 970 Days
• Field of Search: 707768
• CPC Class Codes: G06F 11/14 Error detection or correction of the data by redundancy in operation G06F11/16 takes precedence
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1453 using de-duplication of the data
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• 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 3/06 Digital input from, or digital output to, record carriers , e.g. RAID, emulated record carriers or networked record carriers
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes

Abstract

The disclosed systems and methods enable an application to start operating and servicing users soon after and during the course of its backup data being restored, no matter how long the restore may take. This is referred to as “instant application recovery” in view of the fact that the application may be put back in service soon after the restore operation begins. Any primary data generated by the application during “instant application recovery” is not only retained, but is efficiently updated into restored data. An enhanced data agent and an associated pseudo-storage-device driver, which execute on the same client computing device as the application, enable the application to operate substantially concurrently with a full restore of backed up data. According to the illustrative embodiment, the pseudo-storage-device driver presents a pseudo-volume to the file system associated with the application, such that the pseudo-volume may be used as a store for primary data during the period of “instant application recovery.”

Claims

1. A method comprising:

initiating a restore operation of backed up data from a second storage device to a destination volume on a first storage device, which is in communication with a computing device;

while the restore operation is proceeding to the destination volume using a first mount point configured on the computing device,

mounting to the first mount point a pseudo-volume presented by a driver executing on the computing device;

while the restore operation is proceeding to the destination volume,

starting an application on the computing device that uses the pseudo-volume for the application'"'"'s primary data,

thereby starting the application before the restore operation restores all of the backed up data to the destination volume;

in response to a write request comprising first data blocks issued by the application, storing the first data blocks to a first data structure configured in the pseudo-volume;

in response to a read request for second data blocks issued by the application,

(i) the second data blocks are supplied from the first data structure, when the second data blocks are found therein,

(ii) the second data blocks are supplied from a second data structure configured in the pseudo-volume, when the second data blocks were not found in the first data structure and were found in the second data structure, and

(iii) the second data blocks are fetched from the backed up data in the second storage device when the second data blocks were not found in either of the first data structure and the second data structure; and

after the restore operation restores all of the backed up data to the destination volume;

stopping the application,

updating the destination volume with data blocks stored in the first data structure including the first data blocks,

re-starting the application and using the updated destination volume for the application'"'"'s primary data, and

wherein the stopping, the updating, and the re-starting operations are performed by a data agent that executes on the computing device.

2. The method of claim 1, wherein when the second data blocks are fetched from the backed up data in the second storage device the second data blocks are stored to the second data structure configured in the pseudo-volume.

3. The method of claim 1, wherein the data agent that executes on the computing device processes the write request and the read request from the application.

4. The method of claim 1, further comprising:

after the stopping of the application,

unmounting the pseudo-volume from the first mount point by the, data agent that executes on the computing device.

5. The method of claim 1, wherein the data agent that executes on the computing device processes the write request and the read request from the application;

and

causes the pseudo-volume to be unmounted from the first mount point after the stopping of the application.

6. A method comprising:

executing an application on a computing device while restoring a backup copy, wherein the backup copy represents primary data that was previously generated by the application, based on;

(i) restoring the backup copy to a destination volume configured on a storage device that is mounted to a first mount point of the computing device;

(ii) while the restoring operation is proceeding to the destination volume, executing the application on the computing device, based on using a pseudo-volume as a store for the application'"'"'s primary data, wherein the pseudo-volume is also mounted to the first mount point of the client computing device after the storage device is mounted; and

(iii) processing a read request for first data blocks issued by the application by;

(A) supplying the first data blocks from a second data structure in the pseudo-volume when the first data blocks are found therein,

(B) supplying the first data blocks from a first data structure in the pseudo-volume when the first data blocks were not found in the second data structure and were found in the first data structure, and

(C) causing the first data blocks to be fetched from the backup copy when the first data blocks were not found in either of the first data structure or the second data structure; and

after the restoring of the backup copy to the destination volume is completed, (a) stopping the application, (b) unmounting the pseudo-volume from the first mount point, and (c) updating the destination volume with data blocks stored in the second data structure, including the second data blocks.

7. The method of claim 6 wherein a data agent executing on the computing device performs the processing of the read request for first data blocks issued by the application.

8. The method of claim 6 further comprising:

(iv) processing a write request including second data blocks issued by the application by storing the second data blocks to the second data structure in the pseudo-volume.

9. The method of claim 8 wherein a data agent executing on the computing device performs the processing of the write request including second data blocks issued by the application.

10. The method of claim 6 further comprising:

executing the application again, on the computing device, based on using the updated destination volume as the application'"'"'s store for primary data, thereby providing the application with access to data in the restored backup copy updated by at least the second data blocks from the second data structure, which were generated by the application while the restoring operation was proceeding.

11. The method of claim 6 wherein the pseudo-volume is a logical storage device presented by a driver that executes on the computing device.

12. The method of claim 6 wherein the pseudo-volume comprises the first data structure for storing data blocks retrieved from the backup copy in response to read requests issued by the executing application, and

further comprises the second data structure for storing second data blocks included in write requests issued by the executing application.

13. A computer-readable medium, excluding transitory propagating signals, storing instructions that, when executed by at least one computing device comprising one or more processors and computer memory, cause the computing device to perform operations comprising:

executing an application while restoring a backup copy that represents primary data that was previously generated by the application, based on;

(i) restoring the backup copy to a destination volume configured on a storage device that is mounted to a first mount point of the computing device;

(ii) while the restoring operation is proceeding to the destination volume, executing the application on the client computing device, based on using a pseudo-volume as a store for the application'"'"'s primary data, wherein the pseudo-volume is also mounted to the first mount point of the client computing device after the storage device is mounted;

(iii) processing a read request for first data blocks issued by the application by;

(A) supplying the first data blocks from a second data structure in the pseudo-volume when the first data blocks are found therein,

(B) supplying the first data blocks from a first data structure in the pseudo-volume when the first data blocks were not found in the second data structure and were found in the first data structure, and

(C) causing the first data blocks to be fetched from the backup copy when the first data blocks were not found in either of the first data structure or the second data structure; and

(iv) processing a write request including second data blocks issued by the application by storing the second data blocks to the second data structure in the pseudo-volume; and

after the restoring of the backup copy to the destination volume is completed, (a) stopping the application, (b) unmounting the pseudo-volume from the first mount point, and (c) updating the destination volume with data blocks stored in the second data structure, including the second data blocks.

14. The computer-readable medium of claim 13 wherein a data agent executing on the computing device performs the processing of the read request for first data blocks issued by the application and the processing of the write request including second data blocks issued by the application.

15. The computer-readable medium of claim 13 wherein the operations further comprise:

executing the application again, on the computing device, based on using the updated destination volume as the application'"'"'s store for primary data, thereby providing the application with access to data in the restored backup copy updated by at least the second data blocks from the second data structure, which were generated by the application while the restoring operation was proceeding.

16. The computer-readable medium of claim 13 wherein the pseudo-volume is a logical storage device presented by a driver that executes on the computing device.

17. The computer-readable medium of claim 13, wherein when the second data blocks are fetched from the backed up data in the second storage device the second data blocks are stored to the second data structure configured in the pseudo-volume.