服务器负载均衡算法.pptVIP

12/1/03 服务器负载均衡算法 ---基于Cookie的保持性算法介绍 Topic Cookie是什么？ Insert Cookie算法介绍 Rewrite Cookie算法介绍 Embed Cookie算法介绍 Persistent Cookie算法介绍 Hash Cookie 算法介绍 算法的区别 Cookie算法的适用范围 Cookie算法的配置 Cookies Cookies是一种能够让网站服务器把少量数据储存到客户端的硬盘或内存，或是从客户端的硬盘读取数据的一种技术。 Cookies是当你浏览某网站时，由Web服务器置于你硬盘上的一个非常小的文本文件。 例如：它可以记录你的用户ID、密码、浏览过的网页、停留的时间等信息。 当你再次来到该网站时，网站通过读取Cookies，得知你的相关信息，就可以 做出相应的动作，如在页面显示欢迎你的标语，或者让你不用输入ID、密码就 直接登录等等。 一个Cookie 包含名称和值 举例 Cookie: SID=service3 Cookie 类型 临时的cookie: 当浏览器关闭后自动删除. 永久的cookie: 如果不过期就不删除. Insert Cookie (ic) Array 会自动在服务器响应的时候给客户端插入一个Cookie 步骤： Client sends a request to the virtual service. Array selects a real service and forwards request to it. Response from real service does not contain a cookie, but cookie persistence is needed. Array creates a cookie based on the real service and inserts it in the response. Client receives cookie in response. Next request from client includes cookie. Array examines cookie, strips out cookie, and sends request to same real service as first request. 适用范围：当Web服务没有Cookie的应用. Insert Cookie (ic) Rewrite Cookie (rc) Array 在服务器响应的时候重写 (修改) cookie的值. 步骤： Client sends a request to the virtual service. Array selects a real service and forwards request to it. Response from real service contains a specific cookie with a generic value. Array rewrites cookie value based on the real service. Client receives cookie in response. Next request from client includes cookie. Array examines cookie and sends request to indicated real service. 应用在基于简单Cookie应用的环境中. 所有的后台服务器必须拥有同样的Cookie的名称. Rewrite Cookie (rc) Embed Cookie（ec） 嵌入 cookie允许将所需内容嵌入到cookie值中来确保带有cookie的请求被送回同一个服务器. 步骤： Client sends a request to the virtual service. Array selects a real service and forwards request to it. Response from real service contains a cookie. Array embeds a specific value based on the real service. Client receives cookie in response. Next request from client includes cookie. Array examines cookie and removes the