MANAGING REPLICATED VIRTUAL STORAGE AT RECOVERY SITES

• US 20120324183A1
• Filed: 06/20/2011
• Published: 12/20/2012
• Est. Priority Date: 06/20/2011
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Sinha, Gaurav, Oshins, Jacob, Eck, Christopher L., Chiruvolu, Phani, Singh, Devdeep
• Granted Patent: US 9,785,523 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1484 involving virtual machines
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component
• 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 2201/815 Virtual
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

Techniques involving replication of storage are described. A representative technique includes apparatuses and methods for receiving replicated virtual storage of a replicated virtual machine, including at least a replicated base virtual disk that substantially corresponds to a primary base virtual disk to be replicated. Copies of differencing disks or other forms of virtual storage updates are received at a recovery site, each of the differencing disks being associated with the primary base virtual disk as descendents thereof. The received copies of the differencing disks are arranged relative to the replicated base virtual disk corresponding to the manner in which the differencing disks were arranged relative to the primary base virtual disk, thereby maintaining the data view of the replicated virtual machine in synchronization with the virtual machine at the primary site.

Claims

1. An apparatus comprising:

replicated virtual storage of a replicated virtual machine, including at least a replicated base virtual disk substantially corresponding to a primary base virtual disk to be replicated;

a receiver configured to receive a plurality of copies of differencing disks, of a plurality of copy types, each associated with the primary base virtual disk; and

a replication management module configured to arrange the received copies of the differencing disks of the plurality of copy types relative to the replicated base virtual disk as the differencing disks were arranged relative to the primary base virtual disk.

2. The apparatus of claim 1, wherein a first of the plurality of copy types comprises an application-consistent copy type based on application data that has been prepared for creation of the copy, and wherein a second of the plurality of copy types comprises a crash-consistent copy type based on application data that has not been prepared for creation of the copy.

3. The apparatus of claim 1, wherein the replication management module is further configured to store one or more of the received copies of the differencing disks as potential restoration points for initiating operation of the replicated virtual machine.

4. The apparatus of claim 3, further comprising creating a read-write differencing disk as a child disk to one of the stored copies of the differencing disks to store changes to the replicated virtual machine when initiated.

5. The apparatus of claim 3, wherein the replication management module is further configured to facilitate initiation of the replicated virtual machine from a selected one of the potential restoration points and one or more selected stored copies of the differencing disks that sequentially succeed the selected restoration point.

6. The apparatus of claim 5, wherein the replication management module is further configured to enable reanimation of the replicated virtual machine from the selected one of the potential restoration points, but using one or more different selected stored copies of the differencing disks that also sequentially succeed the selected restoration point.

7. The apparatus of claim 5, wherein the replication management module is further configured to enable reanimation of the replicated virtual machine from a different selected one of the potential restoration points and the one or more selected stored copies of the differencing disks that sequentially succeed the different selected restoration point.

8. The apparatus of claim 1, wherein the replication management module is further configured to merge one or more read-only copies of the differencing disks into their respective parent disks.

9. The apparatus of claim 1, wherein the replication management module is further configured to modify links in the copies of the differencing disks to point to their respective parent disks as arranged for use with the replicated virtual machine.

10. The apparatus of claim 1, wherein the replication management module is configured for implementation in a hypervisor.

11. A computer-implemented method comprising:

storing a base virtual disk image of a virtual disk associated with a virtual machine;

storing changes to the virtual disk by recording the changes to a current read-write differencing disk at the top of a disk chain that includes the base virtual disk image and any intervening differencing disks; and

recurrently creating transferrable copies of the changes to the virtual disk for replicated storage by creating a copy of the current read-write differencing disk and prohibiting further changes thereto, creating a new current differencing disk at the top of the disk chain, and transferring the copies of the differencing disks for the replicated storage.

12. The computer-implemented method of claim 11, wherein creating a copy of the current read-write differencing disk comprises creating a plurality of different types of copies of the current read-write differencing disk, and wherein transferring the copies of the differencing disks comprises transferring each of the different types of copies of the differencing disks for the replicated storage.

13. The computer-implemented method of claim 11, wherein creating a copy of the current read-write differencing disk comprises creating at least two types of copies of the current read-write differencing disk, including at least a first copy type obtained on application data that has been prepared for the copy to be created, and including at least a second copy type obtained on application data that has not been prepared for the copy to be created.

14. The computer-implemented method of claim 13, further comprising notifying one or more applications of an impending copy, and wherein creating the first copy type comprises obtaining the application data from the one or more notified applications that have been prepared for the copy to be created.

15. The computer-implemented method of claim 14, wherein creating the first copy type comprises creating a volume shadow copy service (VSS) snapshot of the current read-write differencing disk.

16. The computer-implemented method of claim 13, wherein creating the second copy type comprises copying a file storing the current read-write differencing disk and configuring the file as read-only, without notifying applications of an impending copy.

17. The computer-implemented method of claim 13, wherein creating at least two types of copies of the current read-write differencing disk comprises creating the copies of the first copy type in connection with a first copy schedule, and creating the copies of the second copy type in connection with a second copy schedule.

18. Computer-readable media having instructions stored thereon which are executable by a computing system for performing steps comprising:

creating a chain of read-only snapshots of a virtual machine'"'"'s differencing disk, with a new differencing disk being created upon each snapshot that provides read and write capability at the tip of the chain;

including a plurality of types of the snapshots on the chain, including at least an application-consistent snapshot type and a crash-consistent snapshot type;

creating a replicated chain of the read-only snapshots that corresponds to the chain of read-only snapshots of the virtual machine'"'"'s differencing disk;

enabling selection of one of the read-only snapshots in the replicated chain as a restoration point for initiating a replicated virtual machine; and

initiating the replicated virtual machine from the selected one of the read-only snapshots and including one or more of the read-only snapshots that follow the selected restoration point in succession.

19. The computer-readable media as in claim 18, wherein the computer-readable media further comprises instructions executable by the computing system for enabling selection of a different one of the read-only snapshots in the replicated chain as a new restoration point for initiating the replicated virtual machine, and wherein initiating the replicated virtual machine comprises initiating the replicated virtual machine from the selected different one of the read-only snapshots and including one or more of the read-only snapshots that follow the new restoration point in succession.

20. The computer-readable media as in claim 18, wherein the computer-readable media further comprises instructions executable by the computing system for facilitating re-initiation of the replicated virtual machine from the selected one of the read-only snapshots while including a different one or more of the read-only snapshots that follow the selected restoration point in succession.