叢集式網站系統的負載平衡機制

Abstract

隨著網際網路的快速發展，興起了以全球資訊網為主的各種應用，為了提供迅速、多樣化的服務，進一步發展出叢集式網站架構，在此架構下，多台伺服器可整合成為單一系統，達成有效的資源共享，藉此提供使用者更穩定的服務品質，此架構也為目前大部分網站所採用。 伺服器的負載平衡在叢集式網站系統中扮演著重要的角色。負載平衡機制的目的是用來平衡網站伺服器的負荷，避免網站伺服器因過多的服務需求而超載，或因過少的服務需求而閒置，以提高系統效能，降低對使用者服務的回應時間。在這篇論文中，我們討論了叢集式網站系統的架構與其負載平衡機制，提出一個透過平均分配網頁文件的方式來達到負載平衡，並評估其效能。

The exponential increase in service on the World Wide Web has created the need for faster web system to provide better quality of services for users. A powerful alternative is clustering several machines as a single web server to outside. The cluster architecture, which becomes the popular solution for most web sites in recent years, can provide better availability, scalability, and resource sharing. Typical cluster-based web system consists of several back-end servers and a front-end dispatcher that routes user requests among servers. In this architecture, the load balancing is one of the key technologies. The main goal of load balancing policy is to prevent the web servers’ load from being unbalanced, and achieve higher system performance. In this thesis, we present a load balancing method for cluster-based web system based on the idea of content partitioning and evaluates its performance.