Virtual machine change block tracking

Patent metadata

Field	Value
Publication number	US-2017109087-A1
Application number	US-201615394556-A
Country	US
Kind code	A1
Filing date	Dec 29, 2016
Priority date	Nov 20, 2014
Publication date	Apr 20, 2017
Grant date	—

Abstract

According to certain aspects, a system includes a client device that includes a virtual machine (VM) executed by a hypervisor, a driver located within the hypervisor, and a data agent. The VM may include a virtual hard disk file and a change block bitmap file. The driver may intercept a first write operation generated by the VM to store data in a first sector, determine an identity of the first sector based on the intercepted write operation, determine an entry in the change block bitmap file that corresponds with the first sector, and modify the entry in the change block bitmap file to indicate that data in the first sector has changed. The data agent may generate an incremental backup of the VM based on the change block bitmap file in response to an instruction from a storage manager, where the incremental backup includes the data in the first sector.

First claim

What is claimed is:

1 . A method of backing up a virtual machine, the method comprising:
intercepting, by a first driver under the control of a first hypervisor which executes on a first client computing device, a first write operation generated by a virtual machine (VM) to store data in a first sector of a virtual hard disk, wherein the VM is executed by the first hypervisor, wherein the VM comprises a virtual hard disk file and a change block bitmap file, and wherein the virtual hard disk file stores data associated with the virtual hard disk; with the first client computing device, accessing the change block bitmap file and modifying a first entry in the change block bitmap file to indicate that data in the first sector has changed; migrating the VM to a second hypervisor which executes on a second client computing device, such that the VM is executed by the second hypervisor following said migrating; intercepting by a second driver under the control of the second hypervisor, a second write operation generated by the VM to store data in a second sector of the virtual hard disk; and with the second client computing device,
accessing the change block bitmap file and modifying a second entry in the change block bitmap file to indicate that data in the second sector has changed,
receiving an instruction to begin an incremental backup of the VM, and
as part of the incremental backup of the VM, reviewing the first and second entries in the change block bitmap file to identify the first and second sectors as sectors to access in gathering data for use in performance of the incremental backup.

2 . The method of claim 1 , further comprising:
parsing the change block bitmap file; identifying each entry in the change block bitmap file that indicates that data in a sector of the virtual hard disk associated with the respective entry has changed; for each identified entry, reading data from the sector of the virtual hard disk associated with the respective entry; and for each identified entry, including the read data in the incremental backup.

3 . The method of claim 1 , wherein the first hypervisor comprises an I/O stack, and wherein the I/O stack comprises the first driver.

4 . The method of claim 1 , further comprising:
intercepting an open operation generated by the VM to open the virtual hard disk file; and begin monitoring the virtual hard disk file in response to intercepting the open operation.

5 . The method of claim 1 , wherein the change block bitmap file is associated with a first period of time.

6 . The method of claim 1 , wherein the first driver forms a part of the first hypervisor.

7 . A system configured to backup a virtual machine, the system comprising:
one or more computing devices comprising computer hardware, wherein the one or more computing devices include:
a hypervisor executed by a client device of the one or more computing devices, the hypervisor configured to:
execute a virtual machine (VM), wherein the VM comprises a virtual hard disk file and a change block file, wherein the virtual hard disk file stores data associated with a virtual hard disk, wherein the VM was migrated from an other client computing device of the one or more computing devices, wherein prior to the migration the VM executed on an other hypervisor included on the other client computing device,
intercept write operations generated by the VM to store data in the virtual hard disk file, and
modify the change block file to indicate sectors on the virtual hard disk that have changed as a result of the write operations; and

a data agent executed by the client device and configured to receive an instruction to begin an incremental backup of the VM, and as part of the incremental backup of the VM:
access the change block file, and
review entries in the change block file made by the client computing device following the migration and by the other client computing device prior to the migration, to determine which sectors in the virtual hard disk to gather data from for use in performance of the incremental backup of the VM.

8 . The system of claim 7 , wherein the hypervisor comprises an I/O stack, and wherein the I/O stack comprises a driver that performs the intercept of the write operations.

9 . The system of claim 7 , wherein the data agent is further configured to:
parse the change block file; identify each entry in the change block bitmap file that indicates that data in a sector associated with the respective entry has changed; for each identified entry, determine an associated sector and read data from the associated sector in the virtual hard disk; and for each identified entry, include the read data in the incremental backup.

10 . The system of claim 7 , wherein the hypervisor is further configured to:
intercept an open operation generated by the VM to open the virtual hard disk file; and begin monitoring the virtual hard disk file in response to intercepting the open operation.

11 . Non-transitory computer-readable memory comprising instructions, which when executed by one or more computers, cause the one or more computers to perform a method for backing up a virtual machine, the method comprising:
intercepting, by a driver under the control of a first hypervisor which executes on a first client computing device, a first write operation generated by a virtual machine (VM) to store data in a first sector of a virtual hard disk, wherein the VM is executed by the first hypervisor, wherein the VM comprises a virtual hard disk file and a change block bitmap file, and wherein the virtual hard disk file stores data associated with the virtual hard disk; with the first client computing device, accessing the change block bitmap file and modifying a first entry in the change block bitmap file to indicate that data in the first sector has changed; migrating the VM to a second hypervisor which executes on a second client computing device, such that the VM is executed by the second hypervisor following said migrating; intercepting by a second driver under the control of the second hypervisor, a second write operation generated by the virtual machine (VM) to store data in a second sector of the virtual hard disk; and with the second client computing device,
accessing the change block bitmap file and modifying a second entry in the change block bitmap file to indicate that data in the second sector has changed;
with the second client computing device,
receiving an instruction from a storage manager to begin an incremental backup of the VM, and
as part of the incremental backup of the VM, reviewing the first and second entries in the change block bitmap file to identify the first and second sectors as sectors to access in gathering data for use in performance of the incremental backup.

12 . The non-transitory computer-readable memory of claim 11 , further comprising:
parsing the change block bitmap file; identifying each entry in the change block bitmap file that indicates that data in a sector associated with the respective entry has changed; for each identified entry, determining associated sector in the virtual hard disk and reading data from the associated sector; and for each identified entry, including the read data in the incremental backup.

13 . The non-transitory computer-readable memory of claim 11 , wherein the hypervisor comprises an I/O stack, and wherein the I/O stack comprises the driver.

14 . The non-transitory computer-readable memory of claim 11 , further comprising:
intercepting an open operation generated by the VM to open the virtual hard disk file; and

Assignees

• Commvault Systems Inc

Inventors

• Dornemann Henry Wallace
• Pawar Rahul S

Classifications

• G06F11/1451

  by selection of backup contents · CPC title

• G06F2201/815

  Virtual · CPC title

• G06F11/1435

  using file system or storage system metadata · CPC title

• G06F16/188

  Virtual file systems · CPC title

• G06F2009/45579

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