A method and system for obtaining differential data between multiple disks of a virtual machine

Abstract

The invention discloses a method and a system for obtaining difference data of multiple magnetic discs of a virtual machine. The method comprises the following steps of after a request for obtaining the difference data of magnetic disc files by a user is received, creating an empty differential magnetic disc; obtaining the number of sectors in a source magnetic disc and the number of sectors in the compared magnetic disc; judging whether the number of sectors in the source magnetic disc is equal to the number of sectors in the compared magnetic disc or not; when the number of sectors in the source magnetic disc is equal to the number of sectors in the compared magnetic disc, gradually obtaining the difference data of the source magnetic disc and the compared magnetic disc according to sectors, and writing the difference data into the empty differential magnetic disc; when the number of sectors in the source magnetic disc is not equal to the number of sectors in the compared magnetic disc, using the smaller one of the number of sectors in the source magnetic disc and the number of sectors in the compared magnetic disc as the comparison times, and gradually obtaining the difference data of the source magnetic disc and the compared magnetic disc according to the sectors. The method has the advantages that by using the sectors as granules to compare the difference data of the magnetic discs, the property is excellent in comparison with the existing global browsing extracting method, and the availability is better in comparison with a bit map-based extracting method; at the premise of fully reducing the host machine CPU (central processing unit) availability and I / O (input / output) occupation, the differential data magnetic disc can be accurately obtained.

Description

technical field [0001] The invention relates to the field of computer applications, in particular to a method and system for acquiring difference data among multiple disks of a virtual machine. Background technique [0002] Virtual machine technology is defined as the software simulation implementation of hardware devices, and the usual usage mode is time-sharing and expensive mainframes. Virtual Machine Monitor (Virtual Machine Monitor, VMM) is the core of virtual machine technology, it is a layer of code between the operating system and computer hardware, used to divide the hardware platform into multiple virtual machines. VMM runs in privileged mode, and its main function is to isolate and manage multiple virtual machines running on the upper layer, arbitrate their access to the underlying hardware, and virtualize a set of virtual hardware environments (including processors) independent of actual hardware for each guest operating system. , memory, I / O devices). The VMM ...

AI Technical Summary

Problems solved by technology

[0004] Obtaining the difference data between two disks is the basis for virtual machines to perform advanced functions such as backup and snapshot. However, during this process, the CPU and I / O of the host machine are generally occupied, which affects the normal operation of other programs on the host machine.

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