Storage Checkpointing in a Mirrored Virtual Machine System

• US 20140025913A1
• Filed: 09/25/2013
• Published: 01/23/2014
• Est. Priority Date: 05/23/2011
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Fuente, Carlos F., Mulcahy, James, Scales, William J.
• Granted Patent: US 9,983,935 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 11/1484 involving virtual machines
• CPC Class Codes: G06F 11/2023 Failover techniques
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency ensuring consistency in mirrored systems G06F11/2064
• CPC Class Codes: G06F 9/3863 using multiple copies of the architectural state, e.g. shadow registers
• CPC Class Codes: G06F 9/45533 Hypervisors; Virtual machine monitors

Abstract

A method and system are provided for storage checkpointing in a mirrored virtual machine system. The method includes a storage controller receiving a modifying operation to storage from a virtual machine and carrying out the modifying operation in a non-destructive manner by saving the modifying operation data to a checkpointing region of storage and preserving the stored previous data state. The method also includes receiving a checkpoint notification and committing modifying operation data from the checkpointing region and releasing the stored previous data state. If a failover notification is received, the storage controller rolls back the physical storage to match a checkpoint state.

Claims

1. A method for storage checkpointing in a mirrored virtual machine system, comprising a storage controller:

receiving a modifying operation to storage from a virtual machine;

carrying out the modifying operation in a non-destructive manner by saving modifying operation data of the modifying operation to a checkpointing region of the storage and preserving a stored previous data state;

receiving a checkpoint notification; and

committing the modifying operation data from the checkpointing region and releasing the stored previous data state.

2. The method as claimed in claim 1, including:

supporting multiple checkpoints, wherein a checkpoint notification includes a checkpoint identifier for distinguishing from other checkpoints.

3. The method as claimed in claim 1, including:

receiving at the storage controller a query to determine which checkpoints exist at a given time.

4. The method as claimed in claim 1, wherein committing the modifying operation includes:

committing the data state of the checkpointing region of the storage; and

releasing the stored previous data state to become a new checkpointing region storage.

5. The method as claimed in claim 1, wherein committing the modifying operations includes:

writing the modifying operation data from the checkpointing region to a physical storage location of the stored previous data state on a physical storage.

6. The method as claimed in claim 5, including:

presenting a logical drive of the storage addressable by a client;

saving the modifying operation data of the modifying operation on the logical drive; and

maintaining a mapping of the logical drive to the physical storage in the checkpointing region.

7. The method as claimed in claim 6, including:

receiving a failover notification; and

rolling back the physical storage to match a checkpoint state.

8. The method as claimed in claim 6, including:

receiving a failover notification with a checkpoint identifier;

rolling back the physical storage to match an identified checkpoint state;

reverting the mapping of the logical drive to the physical storage following the identified checkpoint; and

discarding the modifying operation data in the checkpointing region.

9. The method as claimed in claim 8, wherein a checkpoint identifier associates the checkpoint identifie ith a point-in-time view of the logical drive.

10. The method as claimed in claim 1, wherein carrying out the modifying operation in the non-destructive manner includes one of:

performing a copy-on-write operation or performing a redirect-on-write operation.

11-18. -18. (canceled)