Maintaining consistency using reverse replication during live migration

• US 9,672,120 B2
• Filed: 06/26/2015
• Issued: 06/06/2017
• Est. Priority Date: 06/28/2014
• Status: Active Grant

• Current Assignee: Vmware LLC (Broadcom, Inc.)
• Original Assignee: VMware, Inc. (Broadcom, Inc.)
• Inventors: Langouev, Ilia, Tarasuk-Levin, Gabriel, Dirks, Patrick William Penzias, Kolovson, Curt
• Primary Examiner(s): CHAVIS, JOHN Q
• Application Number:
  US14/752,674
• Publication Number:
  US 20150378847A1
• Time in Patent Office: 711 Days
• Field of Search: 714 19, 718 1
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/1484 involving virtual machines
• CPC Class Codes: G06F 11/1658 Data re-synchronization of a redundant component, or initial sync of replacement, additional or spare unit
• CPC Class Codes: G06F 11/2023 Failover techniques
• 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 2009/4557 Distribution of virtual machine instances; Migration and load balancing
• CPC Class Codes: G06F 2201/815 Virtual
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency
• CPC Class Codes: G06F 2201/855 Details of asynchronous mirroring using a journal to transfer not-yet-mirrored changes
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes

Abstract

Examples maintain consistency of writes for a plurality of VMs during live migration of the plurality from a source host to a destination host. The disclosure intercepts I/O writes to a migrated VM at a destination host and mirrors the I/O writes back to the source host. This “reverse replication” ensures that the CG of the source host is up to date, and that the source host is safe to fail back to if the migration fails.

Claims

1. A system for effectively reversing replication during live migration, said system comprising:

a memory area associated with a computing device, said memory area storing a consistency group (CG) of a plurality of source virtual machines (VMs); and

a processor programmed to;

in response to receiving a request to perform a live migration of the CG of source VMs on one or more source hosts and storage to a plurality of destination VMs on one or more destination hosts and storage, perform the live migration of the CG of the source VMs by transferring data representing the source VMs to the destination hosts and storage;

during the live migration of the CG, intercept input/output (I/O) writes to the migrated source VMs and apply the intercepted I/O writes to the CG on the source hosts; and

restore, in response to a failure during the live migration of the CG, the destination VMs using the CG on the source hosts.

2. The system of claim 1, wherein the processor is further programmed to terminate the source VMs on the source host after migration to the destination host.

3. The system of claim 2, further comprising, after migration, changing a replication bias between the source host and the destination host.

4. The system of claim 1, wherein the processor is further programmed to begin reverse replication again, in response to a failure during live migration.

5. The system of claim 1, further comprising receiving the request to perform the live migration of the source VM on the source host to the destination VM on the destination host.

6. The system of claim 1, wherein the data representing the source VMs is stored on a virtual volume managed by a storage provider.

7. The system of claim 1, wherein the destination host is associated with a hybrid cloud service.

8. The system of claim 1, wherein the processor is programmed to open one or more disks via an application programming interface to perform the live migration.

9. A method comprising utilizing reverse replication during live migration to:

in response to receiving a request to perform a live migration a consistency group (CG) of a plurality of source virtual machines (VMs) on a source host to a plurality of destination VMs on a destination host, performing the live migration of the CG of the source VMs by transferring data representing the source VMs to the destination host;

during the live migration of the CG, intercepting input/output (I/O) writes to the migrated source VMs and applying the intercepted I/O writes to the CG on the source host; and

restoring, in response to a failure during the live migration of the CG, the destination VMs using the CG of the source VMs; and

completing the live migration of the CG from the source host to the destination host, wherein upon completion the I/O writes are no longer intercepted or applied.

10. The method of claim 9, further comprising receiving the request to perform the live migration.

11. The method of claim 9, further comprising notifying a destination VM on the destination host that the live migration has completed.

12. The method of claim 9, further comprising:

executing a destination VM on the destination host using the data after the live migration has completed; and

notifying the source VM that the destination VM has begun execution.

13. The method of claim 9, wherein the data representing the source VMs is stored on a virtual volume managed by a storage provider.

14. The method of claim 13, wherein applying the intercepted I/O writes comprises redirecting I/O writes with an array offload.

15. The method of claim 13, wherein applying the intercepted I/O writes of the migrated source VMs comprises utilizing consistent trip handling.

16. The method of claim 9, wherein the destination host is associated with a hybrid cloud service.

17. The method of claim 9, wherein completing the live migration comprises restarting the live migration after the restoration.

18. One or more computer-readable storage media including computer-executable instructions that, when executed, cause at least one processor to use reverse replication during live migration by:

in response to receiving a request to perform a live migration of a consistency group (CG) of a plurality of source virtual machines (VMs) on a source host to a destination host, performing the live migration of the CG of the source VMs by transferring data representing the source VMs to the destination host, wherein the live migration is performed without migrating any of the data that has already been replicated to the destination host;

during the live migration of the CG, intercepting input/output (I/O) writes to the migrated source VMs and applying the intercepted I/O writes to the CG on the source host;

restoring, in response to a failure during live migration of the CG, the destination VMs using the CG of the source VMs; and

completing the live migration of the CG from the source host to the destination host, wherein upon completion the I/O writes are no longer intercepted or applied.

19. The computer-readable storage media of claim 18, wherein the destination host is associated with a hybrid cloud service.

20. The computer-readable storage media of claim 18, wherein applying the intercepted I/O writes to the CG maintains a consistent write order for the plurality of source VMs in the CG.