Cross-hypervisor live mount of backed up virtual machine data, including management of cache storage for virtual machine data

Patent metadata

Field	Value
Publication number	US-2020241908-A1
Application number	US-201916262753-A
Country	US
Kind code	A1
Filing date	Jan 30, 2019
Priority date	Jan 30, 2019
Publication date	Jul 30, 2020
Grant date	—

Abstract

Illustrative systems and methods enable a virtual machine (“VM”) to be powered up at any hypervisor regardless of hypervisor type, based on live-mounting VM data that was originally backed up into a hypervisor-independent format by a block-level backup operation. Afterwards, the backed up VM executes anywhere anytime without needing to find a hypervisor that is the same as or compatible with the original source VM's hypervisor. The backed up VM payload data is rendered portable to any virtualized platform. Thus, a VM can be powered up at one or more test stations, data center or cloud recovery environments, and/or backup appliances, without the prior-art limitations of finding a same/compatible hypervisor for accessing and using backed up VM data. An illustrative media agent maintains cache storage that acts as a way station for data blocks retrieved from an original backup copy, and stores data blocks written by the live-mounted VM.

First claim

1 . A method comprising:
by a first hypervisor, transmitting to a first virtual disk a first write request for a first data block issued by a first virtual machine that executes on the first hypervisor;
wherein the first hypervisor executes on a first computing device comprising one or more processors and computer memory,
wherein the first virtual disk is configured to store data for the first virtual machine,
wherein the first virtual disk is associated with a backup copy of a second virtual machine,
wherein the backup copy was generated in a hypervisor-independent format by a block-level backup operation of a second virtual disk of the second virtual machine, and
wherein the first virtual disk is configured in cache storage that is mounted to the first hypervisor as native data storage for virtual machines that are to execute thereupon, including the first virtual machine;
by a media agent that maintains the cache storage, intercepting the first write request transmitted to the first virtual disk,
wherein the media agent executes on a second computing device comprising the cache storage, one or more processors, and computer memory;
by the media agent, storing the first data block to the first virtual disk; based on determining by the media agent that storage space in the first virtual disk is below a predefined threshold, identifying by the media agent the first data block as being least recently used in the first virtual disk; and based on determining by the media agent that the first data block was written by the first virtual machine, declining to discard the first data block from the first virtual disk.

2 . The method of claim 1 , wherein the media agent keeps track of data blocks written to the first virtual disk resulting from write requests issued by the first virtual machine, including the first data block.

3 . The method of claim 1 , wherein the determining by the media agent that the first data block was written by the first virtual machine is based on the media agent keeping track of data blocks written to the first virtual disk resulting from write requests issued by the first virtual machine, including the first data block.

4 . The method of claim 1 further comprising:
based on determining by the media agent that the first data block is in the first virtual disk, serving the first data block from the first virtual disk to the first hypervisor in response to a second read request issued by the first virtual machine, thereby providing the first data block generated by the first virtual machine from the cache storage.

5 . The method of claim 1 , further comprising:
based on the media agent declining to discard the first data block from the first virtual disk, identifying by the media agent in the first virtual disk a second data block that is least recently used by the first virtual machine; and based on determining by the media agent that the second data block was not written by the first virtual machine and has been read from the backup copy of the second virtual machine that is associated with the first virtual disk, discarding the second data block from the first virtual disk, thereby saving storage space allocated to the first virtual disk in the cache storage.

6 . The method of claim 1 , further comprising:
based on determining by the media agent that storage space in the first virtual disk is below the predefined threshold, identifying by the media agent in the first virtual disk a second data block that is least recently used by the first virtual machine; and based on determining by the media agent that the second data block was not written by the first virtual machine and has been read by the first virtual machine more often than a predefined threshold, declining to discard the second data block from the first virtual disk in the cache storage.

7 . The method of claim 1 , further comprising:
based on determining by the media agent that storage space in the first virtual disk is below the predefined threshold, identifying by the media agent in the first virtual disk a second data block that is least recently used by the first virtual machine; and based on determining by the media agent that the second data block was not written by the first virtual machine and has been read by the first virtual machine less often than a predefined threshold, discarding the second data block from the first virtual disk in the cache storage.

8 . The method of claim 1 , wherein the cache storage comprises a plurality of virtual disks, each one corresponding to a respective virtual machine that executes on the first hypervisor; and
wherein each virtual disk in the plurality of virtual disks is associated with the backup copy of the second virtual machine, thereby enabling each respective virtual machine to use data blocks from the backup copy of the second virtual machine.

9 . The method of claim 1 , wherein the cache storage comprises a plurality of virtual disks, each one corresponding to a respective virtual machine that executes on the first hypervisor; and
wherein each virtual disk in the plurality of virtual disks is associated with the backup copy of the second virtual machine,
thereby enabling each respective virtual machine to use data blocks from the backup copy of the second virtual machine independently of which data blocks from the backup copy are used by other respective virtual machines that execute on the first hypervisor.

10 . The method of claim 1 , further comprising:
by the first hypervisor, transmitting to the first virtual disk a first read request issued by the first virtual machine for a second data block; by the media agent, intercepting the first read request transmitted to the first virtual disk, based on determining by the media agent that the second data block is not in the first virtual disk, by the media agent: (i) reading the second data block from the backup copy, and (ii) storing the second data block to the first virtual disk; and based on determining by the media agent that the second data block is in the first virtual disk, serving the second data block from the first virtual disk to the first hypervisor, thereby providing the second data block from the backup copy of the second virtual machine to the first virtual machine.

11 . A method comprising:
powering on a first virtual machine on a first hypervisor,
wherein a first virtual disk is configured to store data for the first virtual machine,
wherein the first virtual disk is associated with a backup copy of a second virtual machine,
wherein the backup copy was generated in a hypervisor-independent format by a block-level backup operation of a second virtual disk of the second virtual machine,
wherein the first virtual disk is configured in cache storage mounted to the first hypervisor before the first virtual machine was powered on,
wherein the first hypervisor executes on a first computing device comprising one or more processors and computer memory;
by the first hypervisor, transmitting to the first virtual disk a first write request issued by the first virtual machine for a first data block; by a media agent that maintains the cache storage, intercepting the first write request transmitted to the first virtual disk,
wherein the media agent executes on a second computing device comprising the cache storage, one or more processors, and
computer memory; by the media agent, storing the first data block to the first virtual disk; by the media agent, keeping track of data blocks being written to the first virtual disk resulting from write requests issued by the first virtual machine; based on determining by the media agent that storage space in the fir

Assignees

• Commvault Systems Inc

Inventors

• Dornemann Henry Wallace
• Mitkar Amit
• Kumar Sanjay
• Kilaru Satish Chandra
• Degaonkar Sumedh Pramod

Classifications

• G06F11/2094

  Redundant storage or storage space (G06F11/2056 takes precedence) · CPC title

• G06F2201/815

  Virtual · CPC title

• G06F11/2076

  Synchronous techniques · CPC title

• G06F11/1464

  for networked environments · CPC title

• G06F2009/45575

  Starting, stopping, suspending or resuming virtual machine instances · CPC title