nginx在网站中的7层转发功能

  ＿＿＿＿＿＿＿＿＿＿＿＿ client
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                 +-----------------[LVS]   LVS并发访问量400万
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                +
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          ---------------------------
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        Nginx       Nginx       Nginx
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                 +
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apache     apache    apache     squid    squid   squid    tomcat  tomcat      tomcat