System and method for storage during virtual machine migration

Patent metadata

Field	Value
Publication number	US-11074099-B2
Application number	US-201916715950-A
Country	US
Kind code	B2
Filing date	Dec 16, 2019
Priority date	Feb 6, 2018
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

A system and method receiving a request to transfer first data from a first storage space to a second storage space, receiving a write request to write second data to a location during the transfer of the first data, determining from an access data structure that the location is not in use, writing the second data to the second storage space, and updating a location data structure indicating the location of the second data to be in the second storage space.

First claim

What is claimed is:

1. A method comprising:
receiving a request to transfer first data from a first storage space to a second storage space;
creating an access data structure upon receiving the request to transfer the first data from the first storage space to the second storage space;
receiving a write request to write second data to a location during the transfer of the first data;
determining from the access data structure that the location is not in use;
writing the second data to the second storage space; and
updating a location data structure indicating the location of the second data to be in the second storage space.

2. The method of claim 1 further comprising:
receiving a read request to read third data;
determining from the location data structure whether the third data is located in the first storage space or the second storage space; and
reading the third data from the first storage space if the third data is in the first storage space or from the second storage space if the third data is in the second storage space.

3. The method of claim 1 , wherein one of the first storage space or the second storage space is an allocated storage space for a virtual machine.

4. The method of claim 1 , wherein the first storage space and the second storage space is part of a storage pool.

5. The method of claim 1 , further comprising creating the location data structure upon receiving the request to transfer the first data from the first storage space to the second storage space.

6. The method of claim 1 , wherein the first data comprises a plurality of data portions, and wherein for each of the plurality of data portions, the access data structure indicates whether a particular one of the plurality of data portions is in use.

7. The method of claim 1 , wherein the first data comprises a plurality of data portions, and wherein for each of the plurality of data portions, the location data structure indicates whether a particular one of the plurality of data portions is in the first storage space or the second storage space.

8. A method comprising:
receiving a request to migrate a virtual machine from a first host machine to a second host machine, wherein the virtual machine comprises data stored in a first storage associated with the first host machine before the migration, and wherein the first storage is not accessible to the second host machine;
creating an access data structure upon receiving the request, wherein the access data structure indicates whether the data is in use;
transferring the data from the first storage to a shared storage space in response to the request upon determining that the data is not in use, wherein the shared storage space is accessible to both the first host machine and the second host machine; and
migrating the virtual machine from the first host machine to the second host machine upon transferring the data to the shared storage space.

9. The method of claim 8 , further comprising, upon migrating the virtual machine to the second host machine, transferring the data from the shared storage space to a second storage associated with the second host machine, wherein the second storage is not accessible to the first host machine.

10. The method of claim 8 , wherein the data comprises a plurality of data portions, and wherein for each of the plurality of data portions, the access data structure indicates whether a particular one of the plurality of data portions is in use.

11. The method of claim 10 , further comprising:
determining, from the access data structure, that a first data portion of the plurality of data portions is not in use;
annotating the access data structure to indicate that the first data portion is in use in preparation for the transfer;
transferring the first data portion from the first storage to the shared storage space; and
annotating the access data structure after the transfer is complete to indicate that the first data portion is not in use.

12. The method of claim 8 , further comprising creating a location data structure upon receiving the request, wherein the data comprises a plurality of data portions, and wherein for each of the plurality of data portions, the location data structure indicates whether a particular one of the plurality of data portions is in the first storage or the shared storage space.

13. The method of claim 12 , further comprising:
determining, from the location data structure, that a first data portion of the plurality of data portions is in the first storage before the transfer;
transferring the first data portion from the first storage to the shared storage space; and
annotating the location data structure after the transfer to indicate that the first data portion is in the shared storage space.

14. The method of claim 8 , wherein the shared storage space is part of a storage pool.

15. A non-transitory computer-readable media with computer-executable instructions embodied thereon that cause a processor to perform a process comprising:
receiving a request to transfer first data from a shared storage space to a local virtual disk;
creating an access data structure for the first data, wherein the access data structure is annotated to indicate that the first data is in use in preparation for the transfer;
creating a location data structure for the first data, wherein the location data structure is annotated to indicate that the first data is in the shared storage space before the transfer;
transferring the first data from the shared storage space to the local virtual disk; and
after the transfer, annotating the access data structure to indicate that the first data is not in use and annotating the location data structure to indicate that the first data is in the local virtual disk.

16. The non-transitory computer-readable media of claim 15 , further comprising:
receiving a write request to write second data to a location of the first data;
determining from the access data structure that the location is not in use; and
writing the second data to the local virtual disk regardless of whether the first data is in the shared storage space or the local virtual disk.

17. The non-transitory computer-readable media of claim 15 , further comprising:
receiving a write request to write second data to a location of the first data;
determining from the access data structure that the location is not in use;
determining from the location data structure that the location is in the shared storage space; and
writing the second data to the shared storage space.

18. The non-transitory computer-readable media of claim 15 , further comprising:
receiving a write request to write second data to a location of the first data;
determining from the access data structure that the location is not in use;
determining from the location data structure that the location is in the local virtual disk; and
writing the second data to the local virtual disk.

19. The non-transitory computer-readable media of claim 15 , wherein each of the access data structure and the location data structure is a bitmap.

20. The non-transitory computer-readable media of claim 15 , further comprising:
receiving a read request to read second data;
determining from the location data structure whether the second data is located in the shared storage space or the local virtual disk; and
reading the second data from the shared storage space if the second data is in the shared storage space or from the local virtual disk if the second data is in the loca

Assignees

• Nutanix Inc

Inventors

• Franciosi Felipe
• Turschmid Peter
• Crossley Malcolm

Classifications

• G06F2009/45579

  I/O management, e.g. providing access to device drivers or storage · CPC title

• G06F3/0664

  at device level, e.g. emulation of a storage device or system · CPC title

• G06F3/0604

  Improving or facilitating administration, e.g. storage management · CPC title

• G06F3/0647 Primary

  Migration mechanisms · CPC title

• G06F3/067

  Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS] · CPC title