虛擬機器自動容錯技術是採用備援虛擬機器的方式，將主要虛擬機器的狀態不斷的同步至另一台實體機器，當主要虛擬機器因任何因素導致服務終止時，備援虛擬機器會立刻接手繼續提供服務，讓主要虛擬機器原先運行的服務不會因此中斷。但根據我們的研究，目前基於KVM的開源容錯如Kemari和Micro-Checkpointing並無法提供一個可以讓網路服務順暢運作的環境，因此中央大學資訊工程研究所的研究團隊提出了一個針對網路服務的容錯架構M-FTVM，而此架構能降低容錯系統對於雲端網路服務的影響。本研究承襲了這樣的容錯架構，並進行錯誤修正，解決了前版本備援虛擬機器對主要虛擬機器生命週期產生影響的問題，經過實驗的測試，問題修正後效能與前版本並無太大損失，而且和其他基於KVM的開源容錯相比我們的容錯系統在網路服務方面效能優異許多。

Automatic fault tolerance for virtual machine usually uses a backup virtual machine to protect the primary virtual machine, which provides services to end users. The primary and the backup virtual machines have to run on different physical machines and keep their states synchronized. As the primary virtual machine fails, the backup virtual machine has to take the control and keeps the services on the virtual machine alive. Based on our study, the existing open-source projects of virtual machine fault tolerance, Kemari and Micro-Checkpointing, do not have good performance when hosting a network service. Therefore, we have proposed a novel design of a fault-tolerant virtual machine based on KVM, namely M –FTVM. We have also implemented a prototype of the proposed fault-tolerant virtual machine, and keep working on improving its performance and correctness. This paper focus on the issue of the virtual machine life cycle on the original M-FTVM. That is, the backup virtual machine may cause the primary virtual machine unstable and affects the life cycle of virtual machine. Therefore, we propose a new design for the virtual machine life cycle of M-FTVM, and modified the implementation of M-FTVM accordingly. The experiment results show that, the new design does not cause much overhead when compared with the original M-FTVM.

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