Accessing virtual data storage units to offload operations from a computer system hosting a virtual machine to an offload server

• US 7,707,185 B1
• Filed: 10/19/2006
• Issued: 04/27/2010
• Est. Priority Date: 10/19/2006
• Status: Active Grant

• Current Assignee: Vmware LLC (Broadcom, Inc.)
• Original Assignee: VMware, Inc. (Broadcom, Inc.)
• Inventors: Chuang, Shaw C., Yadappanavar, Krishna, Le, Bich Cau, Czezatke, Christian
• Primary Examiner(s): Trujillo; James
• Assistant Examiner(s): Casanova; Jorge A
• Application Number:
  US11/584,395
• Time in Patent Office: 1,286 Days
• Field of Search: 707202-204, 711/162, 718/1
• US Class Current: 707/649
• CPC Class Codes: G06F 11/1466 to make the backup process non-disruptive
• CPC Class Codes: G06F 2009/45579 I/O management, e.g. providing access to device drivers or storage
• CPC Class Codes: G06F 2201/815 Virtual middleware or OS functionality using virtual machines to implement generic software techniques for error detection or fault masking G06F11/1484
• CPC Class Codes: G06F 2209/509 Offload
• CPC Class Codes: G06F 9/45504 Abstract machines for programme code execution, e.g. Java virtual machine [JVM], interpreters, emulators
• CPC Class Codes: G06F 9/5044 considering hardware capabilities
• CPC Class Codes: G06F 9/5055 considering software capabilities, i.e. software resources associated or available to the machine

Abstract

A process of providing access to data associated with a virtual machine running on a host computer system to an offload server is implemented to improve the performance of the host computer system. Once the offload computer system knows how and where to access the data associated with that of the virtual machine, operations can be offloaded from the host computer system and performed by the offload server. Backup operations can be offloaded onto the server. The server can run backup software and directly access the data associated with the virtual machine, thereby freeing the hardware resources of the host computer to handle normal applications running on the virtual machine.

Claims

1. A method for providing access to disk data of a virtual machine running on a first computer system hosting the virtual machine to a second computer system:

storing data corresponding to the virtual machine as logical blocks in a physical persistent storage attached to the first computer system;

quiesceing all applications running on the virtual machine;

taking a snapshot of the data;

creating a logical to physical mapping for the snapshot of the data, wherein the mapping is provided by the virtual machine and stored within the snapshot of the data, wherein the mapping defines correlation between virtual blocks to which the virtual machine saves the data and physical blocks to which the data is persistently stored; and

reading the data residing in the snapshot by the second computer system according to the mapping, without starting a virtual machine for the snapshot on the first computer system, wherein the second computer system reads data in the snapshot directly without using a virtual machine.

2. The method of claim 1 further comprising:

running backup software on the second computer system to backup the data corresponding to the virtual machine, wherein the second computer system directly accesses the data residing on the physical server according to the logical to physical mapping.

3. The method of claim 1, wherein the data corresponding to the virtual machine is stored in a virtual data storage unit.

4. The method of claim 1, wherein the accessing is enabled by the logical to physical mapping provided by the computer system hosting the virtual machine.

5. The method of claim 1 wherein the second computer system comprises an offload server which runs software to execute tasks on the data corresponding to the virtual machine with minimal impact to applications running on the virtual machine.

6. The method of claim 1 further comprising:

caching metadata which specify the logical to physical mapping.

7. A method for backing up a virtual machine running on a host computer system comprising:

presenting a copy of disk data corresponding to the virtual machine at a specific, known time;

creating a logical view of snapshot data, wherein the logical view is provided by the virtual machine and stored within the snapshot, wherein the logical view defines correlation between virtual blocks to which the virtual machine saves data and physical blocks to which the data is persistently stored;

accessing from a second computer the snapshot that is stored in the host computer according to the logical view to read the snapshot data directly without using a virtual machine and without starting a virtual machine for the snapshot on the host computer;

writing the data to a backup storage medium using the second computer system.

8. The method of claim 7 further comprising:

quiesceing the virtual machine before writing the copy of data.

9. The method of claim 7 further comprising:

installing backup software only on the second computer system to backup the data corresponding to the virtual machine.

10. The method of claim 7 further comprising:

defining a mapping which maps the logical view to locations of the physical persistent storage containing the snapshot data.

11. The method of claim 7 further comprising:

the second computer system directly reading the snapshot data from the physical persistent storage over a storage area network.

12. The method of claim 7 further comprising:

running an application on the virtual machine while virtual machine files are being backed up by the second computer system.

13. The method of claim 7, wherein the second computer system comprises an offload physical server.

14. The method of claim 7 further comprising:

transmitting metadata to the second computer system, wherein the metadata defines a plurality of logical to physical persistent storage mappings which are used by the second computer system to access the data to be backed up.

15. A computer system comprising:

a processor for running applications on a virtual machine;

an input/output interface coupled to the virtual memory for transmitting metadata which specifies a logical to physical mapping which is used by an external computer system to perform backup operations on the data stored in a disk memory, wherein the input/out interface is configured to provide the logical to physical mapping to external computer system and the external computer system accesses a snapshot of data of the virtual machine directly without using a virtual machine and without starting the virtual machine for the snapshot on the computer system, wherein the logical to physical mapping defines correlation between virtual blocks to which the virtual machine saves the data and physical blocks to which the data is persistently stored.

16. The computer system of claim 15 further comprising a plurality of virtual machines running on the computer system.

17. The computer system of claim 15 comprising a plurality of virtual data storage units for storing the data generated by the virtual machine.

18. The computer system of claim 15 further comprising a physical data storage unit coupled to the processor having blocks of data corresponding to the virtual machine, wherein these blocks of data are identified to the external computer system and are directly accessed through a dedicated link for backing up the blocks of data.

19. The computer system of claim 15, wherein the virtual machine is quiesced and a snapshot is taken for purposes of backup operations by the external computer.

20. The computer system of claim 15, wherein the external computer performs backup operations while applications are run on the virtual machine.

21. The computer system of claim 15, wherein the logical to physical mapping is specified according to a blocklist protocol.