雲端基礎設施即服務(IaaS)的供應商藉由虛擬化技術將資源從實體機器中獨立出來出租給使用者做其所需的應用服務，已經是雲端運算發展到目前最常見的商業運作模式，然而使用者對於可用性仍舊有很大的顧慮。影響到雲端機房的可用性原因非常多，因為各種硬體元件的毀損影響服務正常運作非常常見，本研究探討機殼風扇毀損造成CPU過熱的熱緊急事件，以期能在發生當機之前將危險排除。
我們設計出一套管理機制，能從溫度資訊與負載量判斷主機是否出錯並且預測到達危險所剩餘的時間。藉由虛擬機器搬遷技術，能夠有效的降低危險機器負載，進而降低危險主機溫度並脫離危險。我們提出轉移時間內送出的熱量作為挑選移出VM的指標，並且提出考量機器耐熱能力的負載平衡演算法作為挑選VM合適的目的地，提升整體系統可用性。根據模擬結果顯示，我們提出的管理機制與演算法能夠有效提升整體系統的可用性，降低VM的失效次數，達成確保服務品質的目標。

Cloud computing, such as Infrastructure as a Service (IaaS), enables a vendor to use virtualization technology to rent computing resources on a physical machine for executing users’ desired applications. IaaS has been the most common business model of cloud computing, but its availability is still a concern among users. Many factors affect the availability of a cloud computing center, such as interruption of service caused by hardware component damage. In this study, we focus on the thermal emergency event of CPU overheating caused by chassis fan damage, and we find a way to resolve the crisis before a crash occurs. We design a Thermal-Aware VM Migration Manager that can determine the health of a physical machine from its temperature and resource utilization information. Through the leveraging of VM migration, the endangered physical machine can be removed from danger by transferring its load to a normal one and reducing the CPU temperature. We propose heat transfer in migration time as criteria for VM selection policy and load balance algorithm with concern for thermal tolerance as VM allocation policy. The simulation results show that a Thermal-Aware VM Migration Manager with our proposed VM selection and allocation policy can enhance system ability and reduce the number of VMs failure.

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