Change tracking for shared disks

• US 8,473,462 B1
• Filed: 04/21/2011
• Issued: 06/25/2013
• Est. Priority Date: 04/21/2011
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Inventors: Banerjee, Amitrajit
• Primary Examiner(s): Hoang, Son T
• Application Number:
  US13/091,239
• Time in Patent Office: 796 Days
• Field of Search: 707/640, 707/661
• US Class Current: 707/640
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 16/13 File access structures, e.g. distributed indices arrangements of input from, or output to, record carriers G06F3/06
• CPC Class Codes: G06F 16/176 Support for shared access to files; File sharing support

Abstract

Various systems and methods for tracking changes in a storage device. For example, one method can involve receiving a request to perform an incremental backup of a storage device and backing up locations in the storage device that are identified as having been changed. The method also involves receiving information from each of the nodes, where the information identifies locations that have been changed by the nodes. The locations that have been changed include both data and metadata.

Claims

1. A method utilizing a computer for tracking changes in shared storage devices comprising:

receiving a request to perform an incremental backup of a storage device, wherein the storage device is accessed by a plurality of nodes;

generating a respective set of information by each of the plurality of nodes, wherein the generating comprises

detecting input/output (I/O) operations, using a disk upper filter driver on a respective node, directed to a portion of the storage device or directed to a host operating system;

in response to detecting the I/O operations are directed to the host operating system, passing a subset of the I/O operations to a file system driver stack and then to a storage device driver stack,

in response to detecting the I/O operations are directed to a portion of the storage device, passing the subset of the I/O operations to the storage device driver stack and bypassing the file system driver stack,

receiving the respective set of information from each of the plurality of nodes in response to the request, wherein

the respective set of information comprises a change list that identifies locations in the storage device that have been modified by the respective node, and

the locations comprise change data and metadata of the change data; and

performing a backup operation comprising copying, to a backup device, change data from each of the locations identified in each of the sets of information, wherein the change data only occurs after a last backup operation is performed.

2. The method of claim 1, wherein

the storage device driver stack is a group of related drivers that cooperate to handle I/O operations of the storage device, and

the file system driver stack is a group of related drivers that cooperate to handle I/O operations of the file system.

3. The method of claim 1, wherein

the storage device comprises a plurality of virtual hard disks (VHDs), wherein

each VHD of the plurality of VHDs corresponds to a respective virtual machine of a plurality of virtual machines, and

the plurality of virtual machines is implemented on the nodes.

4. The method of claim 1, further comprising:

collating all sets of information received from the nodes, wherein the collating is performed by a coordinator node, and

the coordinator node has exclusive rights to modify the metadata for the storage device.

5. The method of claim 1, wherein:

the storage device driver stack is maintained by the host operating system, and the file system driver stack is maintained by the file system.

6. The method of claim 1, wherein

the plurality of nodes comprises a coordinator node and a non-coordinator node, and

the metadata is directly accessible only by the coordinator node.

7. The method of claim 1, wherein

a first node implements a plurality of virtual machines, and

the first node collates information identifying I/O requests generated by each virtual machine of the plurality of virtual machines.

8. A non-transitory computer readable storage medium storing program instructions executable to track changes in shared storage devices, wherein the program instructions are configured to:

receive a request to perform an incremental backup of a storage device, wherein the storage device is accessed by a plurality of nodes;

generate a respective set of information by each of the plurality of nodes, wherein the program instructions are further configured to;

detect input/output (I/O) operations, using a disk upper filter driver on a respective node, directed to a portion of the storage device or directed to a host operating system;

in response to detecting the I/O operations are directed to the host operating system, pass a subset of the I/O operations to a file system driver stack and then to a storage device driver stack,

in response to detecting the I/O operations are directed to a portion of the storage device, pass the subset of the I/O operations to the storage device driver stack and bypass the file system driver stack,

receive the respective set of information from each of the plurality of nodes in response to the request, wherein

the respective set of information comprises a change list that identifies locations in the storage device that have been modified by the respective node, and

the locations comprise change data and metadata of the change data; and

perform a backup operation comprising copying, to a backup device, change data from each of the locations identified in each of the sets of information, wherein the change data only occurs after a last backup operation is performed.

9. The non-transitory computer readable storage medium of claim 8, wherein

the storage device driver stack is a group of related drivers that cooperate to handle I/O operations of the storage device, and

the file system driver stack is a group of related drivers that cooperate to handle I/O operations of the file system.

10. The non-transitory computer readable storage medium of claim 8, wherein the storage device comprises a plurality of virtual hard disks (VHDs), wherein

each VHD of the plurality of VHDs corresponds to a respective virtual machine of a plurality of virtual machines, and

the plurality of virtual machines is implemented on the nodes.

11. The non-transitory computer readable storage medium of claim 8, wherein the program instructions are further configured to:

collate all sets of information received from the nodes, wherein

collating the information is performed by a coordinator node, and

the coordinator node has exclusive rights to modify the metadata for the storage device.

12. The non-transitory computer readable storage medium of claim 8, wherein

the storage device driver stack is maintained by the host operating system, and the file system driver stack is maintained by the file system.

13. The non-transitory computer readable storage medium of claim 8, wherein

the plurality of nodes comprises a coordinator node and a non-coordinator node, and

the metadata is directly accessible only by the coordinator node.

14. The computer readable storage medium of claim 8, wherein

a first node implements a plurality of virtual machines, and

the first node collates information identifying I/O requests generated by each virtual machine of the plurality of virtual machines.

15. A system for tracking changes in shared storage devices comprising:

one or more computer processors; and

a computer memory coupled to the one or more computer processors, wherein the computer memory stores program instructions executable by the one or more computer processors to;

receive a request to perform an incremental backup of a storage device, wherein the storage device is accessed by a plurality of nodes;

generate a respective set of information by each of the plurality of nodes, wherein the program instructions are further configured to;

detect input/output (I/O) operations, using a disk upper filter driver on a respective node, directed to a portion of the storage device or directed to a host operating system;

in response to detecting the I/O operations are directed to the host operating system, pass a subset of the I/O operations to a file system driver stack and then to a storage device driver stack,

in response to detecting the I/O operations are directed to a portion of the storage device, pass the subset of the I/O operations to the storage device driver stack and bypass the file system driver stack,

receive the respective set of information from each of the plurality of nodes in response to the request, wherein

the respective set of information comprises a change list that identifies locations in the storage device that have been modified by the respective node, and

the locations comprise change data and metadata of the change data; and

perform a backup operation comprising copying, to a backup device, change data from each of the locations identified in each of the sets of information, wherein the change data only occurs after a last backup operation is performed.

16. The system of claim 15, wherein

the storage device driver stack is a group of related drivers that cooperate to handle I/O operations of the storage device, and

the file system driver stack is a group of related drivers that cooperate to handle I/O operations of the file system.

17. The system of claim 15, wherein

the storage device comprises a plurality of virtual hard disks (VHDs), wherein

each VHD of the plurality of VHDs corresponds to a respective virtual machine of a plurality of virtual machines, and

the plurality of virtual machines is implemented on the nodes.

18. The system of claim 15, wherein the program instructions are further configured to:

collate the information received from the nodes, wherein

collating all sets of information is performed by a coordinator node, and

the coordinator node has exclusive rights to modify the metadata for the storage device.

19. The system of claim 15, wherein

the storage device driver stack is maintained by the host operating system, and the file system driver stack is maintained by the file system.

20. The system of claim 15, wherein

the plurality of nodes comprises a coordinator node and a non-coordinator node, and

the metadata is directly accessible only by the coordinator node.