網路Web伺服器叢集負載平衡機制之探討-以中興大學網路選課系統為例

Abstract

Web 伺服器叢集已成為網頁服務的主機架構，中興大學以Web 伺服器叢集架構實施網路選課多年。探討本校網路選課情形，分析學生網路選課日誌，選課前30 分是系統的尖峰時期亦是伺服主機服務的危機時期。一般以行政程序規範使用者網路行為或購置Layer4~Layer7 的網路交換設備搭配伺服器叢集或擴增Web cluster 主機數量，來解決Web 伺服器的危機時期。本文測試Layer4~ Layer7網路交換設備之proxy 與switch base 兩種作業模式，對系統效能之影響。並提出以溝通為基礎的觀念，以後端資料庫的效能，作為負載平衡機制啟動的參考，期能以較經濟的設備，讓使用者得知真正處理互動需求回應的後端資料庫的系統狀態，減少盲目上網，讓系統能正常的運作。

Web server cluster has become the main engine overhead construction. National ChungHsing University has been using the web server cluster to select classes for many years. Having discussed the situation of using the school network to select classes and analyzed the student class-selecting registration web log, and the period of previous 30 minutes prior to students selecting classes are the rush hour of the entire system as well as the crisis period of the host server, which is generally solved by either setting up rules to regulate users, purchasing Layer4-Layer7 network commutation equipment to match the server, or expanding the quantities of the main engines of the web cluster. This study is to test how the 2 types of works patterns of Layer4-Layer7 network commutation equipment, Proxy and Switch Base, can influence the system, and bring up the notion based on communication, using database server as a reference to load balance mechanism. It has been expected that by using more economical equipment, users will get to know the database server status of the true interaction, and put the system on a smooth and normal track by reducing the aimless access to the network.