新浪采用了ChinaCache做的CDN系统,ChinaCache在全国分布了四十多个点,同时采用基于动态DNS分配的全球服务器负载均衡技术。

  从新浪的站点结构可以看出:

  > www.sina.com.cn

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: libra.sina.com.cn

  Addresses: 61.135.152.71, 61.135.152.72, 61.135.152.73, 61.135.152.74 61.135.152.75, 61.135.152.76, 61.135.153.181, 61.135.153.182, 61.135.53.183, 61.135.153.184, 61.135.152.65, 61.135.152.66, 61.135.152.67, 61.135.12.68, 61.135.152.69, 61.135.152.70

  Aliases: www.sina.com.cn, jupiter.sina.com.cn

  在北京地区ChinaCache将www.sina.com.cn 的网址解析到libra.sina.com.cn,然后libra.sina.com.cn做了DNS负载均衡,将libra.sina.com.cn解析到61.135.152.71等16个ip上,这16个ip分布在北京的多台前台缓存服务器上,使用squid做前台缓存。如果是在其它地区访问http://www.sina.com.cn可能解析刮..??的效果。

  我们再看一个新浪其它频道是指到哪里的:

  > news.sina.com.cn

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: libra.sina.com.cn

  Addresses: 61.135.152.65, 61.135.152.66, 61.135.152.67, 61.135.152.68 61.135.152.69, 61.135.152.70, 61.135.152.71, 61.135.152.72, 61.135.152.73 61.135.153.178, 61.135.153.179, 61.135.153.180, 61.135.153.181, 61.135.153.182 61.135.153.183, 61.135.153.184

  Aliases: news.sina.com.cn, jupiter.sina.com.cn

  可以看出,各个频道的前台缓存集群与www.sina.com.cn的前台缓存集群是相同的。
  2、搜狐

  Sohu与新浪的原理差不多,下面是nslookup的结果:

  > www.sohu.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: pagegrp1.sohu.com

  Addresses: 61.135.132.172, 61.135.132.173, 61.135.132.176, 61.135.133.109 61.135.145.47, 61.135.150.65, 61.135.150.67, 61.135.150.69, 61.135.150.74 61.135.150.75, 61.135.150.113, 61.135.150.145, 61.135.131.73, 61.135.131.91 61.135.131.180, 61.135.131.182, 61.135.131.183, 61.135.132.65, 61.135.

  132.80

  Aliases: www.sohu.com

  只不过libra.sina.com.cn换成了pagegrp1.sohu.com

  我们再来看一下sohu的频道:

  > news.sohu.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: pagegrp1.sohu.com

  Addresses: 61.135.145.47, 61.135.150.65, 61.135.150.67, 61.135.150.69 61.135.150.74, 61.135.150.75, 61.135.150.113, 61.135.150.145, 61.135.131.73 61.135.131.91, 61.135.131.180, 61.135.131.182, 61.135.131.183, 61.135.132.65 61.135.132.80, 61.135.132.172, 61.135.132.173, 61.135.132.176, 61.135.133.109

  Aliases: news.sohu.com

  同新浪相同,用的是同样的服务器群,这可能是因为他们用的都是ChinaCache的服务吧,不过sohu的名字起的有点土,pagegrp1,没有libra,pavo好听,这名字听起来有点像法语,比较浪漫。

  3、网易

  网易似乎没用ChinaCache的服务,下面是nslookup结果:

  > www.163.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: www.163.com

  Addresses: 202.106.168.103, 202.106.168.104, 202.106.168.109, 202.106.168.121 202.108.36.153, 202.108.36.155, 202.108.36.156, 202.108.36.167, 202.108.36.172 202.108.36.196

  直接在www.163.com 这个域名上做了DNS负载均衡。这样的话就要求服务器必须放的非常靠近主节点,才能保证各地的用户访问的速度。

  但163不同的频道是放在不同的缓存集群上的,这与sina,sohu有些不同,等于sina,sohu是按照地区划分服务器集群,而网易按照频道划分服务器集群。

  > 163.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: 163.com

  Addresses: 202.108.36.205, 202.108.36.206, 202.108.36.207, 202.108.36.201 202.108.36.202, 202.108.36.203, 202.108.36.204

  显然,这和www.163.com 不是一个集群,我们再来试一个:

  > sports.163.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: channel.cache.163.com

  Addresses: 202.108.36.136, 202.108.36.208, 202.108.36.209, 202.108.36.210 202.108.36.211, 202.108.36.212, 202.108.36.213

  Aliases: sports.163.com

  可以看出,和上面的集群也是不同的。

4、百度

  百度的前台服务器就不是很多了:

  > www.baidu.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: www.baidu.com

  Addresses: 202.108.250.249, 202.108.249.134

  > baidu.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: baidu.com

  Address: 202.108.250.228

  > mp3.baidu.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: mp3.baidu.com

  Address: 202.108.249.131

  只有www.baidu.com做了两台服务器的集群,频道都用了一台服务器做前台

5、一搜

  > yisou.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: yisou.com

  Addresses: 202.165.102.114, 202.43.217.14, 202.43.217.15, 202.43.217.16 202.43.217.17, 202.165.102.111, 202.165.102.112, 202.165.102.113

  > www.yisou.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: www.yisou.com

  Addresses: 202.43.217.17, 202.165.102.111, 202.165.102.112, 202.165.102.113 202.165.102.114, 202.43.217.14, 202.43.217.15, 202.43.217.16

  > mp3.yisou.com

  Server: UnKnown

  Address: 192.168.1.254

  Non-authoritative answer:

  Name: www.yisou.com

  Addresses: 202.165.102.113, 202.165.102.114, 202.43.217.14, 202.43.217.15 202.43.217.16, 202.43.217.17, 202.165.102.111, 22.165.102.112

  Aliases: mp3.yisou.com

  前台做了8台服务器的缓存集群,www.yisou.com和 yisou.com以及mp3.yisou.com是用的同一个集群。

  通过前面的分析我们可以得到一个结论:sina和sohu使用了CDN与GSBL与DNS负载均衡技术,每个地区一组前台服务器群,网易,百度使用了DNS负载均衡技术,每个频道一组前台服务器,一搜使用了DNS负载技术,所有频道共用一组前台服务器集群。