WHY? 为什么用Nginx而不用LVS?

7点理由足以说明一切：
1 、高并发连接： 官方测试能够支撑 5 万并发连接，在实际生产环境中跑到 2 ～ 3 万并发连接数。?
2 、内存消耗少： 在 3 万并发连接下，开启的 10 个 Nginx 进程才消耗 150M 内存（ 15M*10=150M ）。?
3 、配置文件非常简单： 风格跟程序一样通俗易懂。?
4 、成本低廉： Nginx 为开源软件，可以免费使用。而购买 F5 BIG-IP 、 NetScaler 等硬件负载均衡交换机则需要十多万至几十万人民币。?
? 使用 Nginx 做七层负载均衡的理由?
5 、支持 Rewrite 重写规则： 能够根据域名、 URL 的不同，将 HTTP 请求分到不同的后端服务器群组。?
6 、内置的健康检查功能： 如果 Nginx Proxy 后端的某台 Web 服务器宕机了，不会影响前端访问。?
7 、节省带宽： 支持 GZIP 压缩，可以添加浏览器本地缓存的 Header 头。

nginx几个知识点汇总

处理query_string
(1)什么是query_string:
http://i.cnblogs.com/EditPosts.aspx?opt=1

上面链接中的?后面的opt=1就是query_string,即url中？后面的都是
(2)nginx中如何获取到上面的值。本例以query_string有一个key为例，多个就是多个正则引用$1,$2的区别而已
nginx中全局变量$args和$query_string中存放的数据就是请求的url中带的query_string
如何获取query_string中key对应的value呢，以上面的链接为例，就是key:opt 对应的value: 1

方法1：下面使用了permanent，因为使用last没有生效。那个大神给看看是什么原因

location /EditPosts.aspx {

            if ($args ~ opt=(\d+)){

	        set $opt $1;  #将截取到的opt对应的值$1赋值给变量$opt（变量必须以$开头，并且不能与nginx预设的全局变量同名）以备后用。

                rewrite  /(.*)\.aspx  /$1/$opt? permanent;   #最后的？很关键，表示正则结束，不然rewrite后的url会变成/EditPosts/1?opt=1
} }

在正则表达式中可以，可以使用小括号对变量值进行截取，在花括号中使用$1...$9引用截取的值（注意，$后面的数字从1开始的哦）

方法2:

      location /EditPosts.aspx {

            if ($args ~ opt=(\d+)){

                rewrite  /(\w*)\.aspx  /$1/$arg_opt? permanent; #即$arg_query_string中key代表的字符串

            }

        }

log_format及nginx的部分预设全局变量的值：

    log_format  main '$remote_addr - $remote_user [$time_local]  "$uri" - "$request_uri" -"$request" -"$status"     "$http_referer" "$http_user_agent" '

	                 ' "$http_x_forwarded_for"  "$request_time" '

	                 '[$cookie_customerID_cookie_flag] [$args]'

	;	

127.0.0.1 - - [11/Jul/2016:17:11:56 +0800]  "/bbs/index.html" - "/bbs/" -"GET /bbs/ HTTP/1.1" -"200"     "-" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.85 Safari/537.36"  "-"  "0.000" [-] [-]

127.0.0.1 - - [11/Jul/2016:17:11:57 +0800]  "/vender/AdminLTE/AdminLTE.min.css" - "/vender/AdminLTE/AdminLTE.min.css" -"GET /vender/AdminLTE/AdminLTE.min.css HTTP/1.1" -"200"     "http://localhost/bbs/" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.85 Safari/537.36"  "-"  "0.000" [-] [-]

127.0.0.1 - - [11/Jul/2016:17:11:57 +0800]  "/vender/bootstrap_v3.3.5/css/bootstrap.min.css" - "/vender/bootstrap_v3.3.5/css/bootstrap.min.css" -"GET /vender/bootstrap_v3.3.5/css/bootstrap.min.css HTTP/1.1" -"200"     "http://localhost/bbs/" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.85 Safari/537.36"  "-"  "0.000" [-] [-]

粘一个匹配过程：

        location / {

            root   D:/workspace/webapp;

            index  index.html index.htm;

        }

	location /api {

            proxy_pass   http://localhsot:9090/api;

        }

		location /topic/view {

            rewrite  /topic/view/(.*) /topic/#/$1 permanent;

        }		

		location ~ /topic/module/\d+ {

            if ($args ~ type=(\d+)){

			    #set $type $1;

                #rewrite  /topic/module/(\d+)  /hello/#/$1?cid=$type? permanent;

                rewrite  /topic/module/(\d+)  /hello/#/$1?cid=$arg_type? permanent;

            }

            rewrite  /topic/module/(\d+)  /hello/#/$1 permanent;

        }

2016/07/12 18:44:23 [debug] 3580#292: post event 0054E058

2016/07/12 18:44:23 [debug] 3580#292: delete posted event 0054E058
2016/07/12 18:44:23 [debug] 3580#292: accept on 0.0.0.0:80, ready: 0
2016/07/12 18:44:23 [debug] 3580#292: malloc: 00512E08:256
2016/07/12 18:44:23 [debug] 3580#292: *89 accept: 127.0.0.1:49491 fd:400
2016/07/12 18:44:23 [debug] 3580#292: *89 event timer add: 400: 60000:3736476011
2016/07/12 18:44:23 [debug] 3580#292: *89 reusable connection: 1
2016/07/12 18:44:23 [debug] 3580#292: *89 select add event fd:400 ev:0
2016/07/12 18:44:23 [debug] 3580#292: *89 post event 0054E0A8
2016/07/12 18:44:23 [debug] 3580#292: *89 delete posted event 0054E0A8
2016/07/12 18:44:23 [debug] 3580#292: *89 http wait request handler
2016/07/12 18:44:23 [debug] 3580#292: *89 malloc: 005211A0:1024
2016/07/12 18:44:23 [debug] 3580#292: *89 WSARecv: fd:400 rc:0 444 of 1024
2016/07/12 18:44:23 [debug] 3580#292: *89 reusable connection: 0
2016/07/12 18:44:23 [debug] 3580#292: *89 malloc: 00518010:4096
2016/07/12 18:44:23 [debug] 3580#292: *89 http process request line
2016/07/12 18:44:23 [debug] 3580#292: *89 http request line: "GET /topic/module/7?channel=3 HTTP/1.1"
2016/07/12 18:44:23 [debug] 3580#292: *89 http uri: "/topic/module/7"
2016/07/12 18:44:23 [debug] 3580#292: *89 http args: "channel=3"
2016/07/12 18:44:23 [debug] 3580#292: *89 http exten: ""
2016/07/12 18:44:23 [debug] 3580#292: *89 http process request header line
2016/07/12 18:44:23 [debug] 3580#292: *89 http header: "Host: localhost"
2016/07/12 18:44:23 [debug] 3580#292: *89 http header: "Connection: keep-alive"
2016/07/12 18:44:23 [debug] 3580#292: *89 http header: "Upgrade-Insecure-Requests: 1"
2016/07/12 18:44:23 [debug] 3580#292: *89 http header: "User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.106 Safari/537.36"
2016/07/12 18:44:23 [debug] 3580#292: *89 http header: "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8"
2016/07/12 18:44:23 [debug] 3580#292: *89 http header: "Accept-Encoding: gzip, deflate, sdch"
2016/07/12 18:44:23 [debug] 3580#292: *89 http header: "Accept-Language: zh-CN,zh;q=0.8"
2016/07/12 18:44:23 [debug] 3580#292: *89 http header: "Cookie: JSESSIONID=608D2B53198A02DE2B977D976A6DE026"
2016/07/12 18:44:23 [debug] 3580#292: *89 http header done
2016/07/12 18:44:23 [debug] 3580#292: *89 event timer del: 400: 3736476011
2016/07/12 18:44:23 [debug] 3580#292: *89 generic phase: 0
2016/07/12 18:44:23 [debug] 3580#292: *89 rewrite phase: 1
2016/07/12 18:44:23 [debug] 3580#292: *89 test location: "/"
2016/07/12 18:44:23 [debug] 3580#292: *89 test location: "api"
2016/07/12 18:44:23 [debug] 3580#292: *89 test location: "topic/view"
2016/07/12 18:44:23 [debug] 3580#292: *89 test location: ~ "/topic/module/\d+"
2016/07/12 18:44:23 [debug] 3580#292: *89 using configuration "/topic/module/\d+"
2016/07/12 18:44:23 [debug] 3580#292: *89 http cl:-1 max:1048576
2016/07/12 18:44:23 [debug] 3580#292: *89 rewrite phase: 3
2016/07/12 18:44:23 [debug] 3580#292: *89 http script var
2016/07/12 18:44:23 [debug] 3580#292: *89 http script var: "channel=3"
2016/07/12 18:44:23 [debug] 3580#292: *89 http script regex: "channel=(\d+)"
2016/07/12 18:44:23 [notice] 3580#292: *89 "channel=(\d+)" matches "channel=3", client: 127.0.0.1, server: localhost, request: "GET /topic/module/7?channel=3 HTTP/1.1", host: "localhost"
2016/07/12 18:44:23 [debug] 3580#292: *89 http script if
2016/07/12 18:44:23 [debug] 3580#292: *89 http script regex: "/topic/module/(\d+)"
2016/07/12 18:44:23 [notice] 3580#292: *89 "/topic/module/(\d+)" matches "/topic/module/7", client: 127.0.0.1, server: localhost, request: "GET /topic/module/7?channel=3 HTTP/1.1", host: "localhost"
2016/07/12 18:44:23 [debug] 3580#292: *89 http script copy: "/bbs/#/"
2016/07/12 18:44:23 [debug] 3580#292: *89 http script capture: "7"
2016/07/12 18:44:23 [debug] 3580#292: *89 http script copy: "?cid="
2016/07/12 18:44:23 [debug] 3580#292: *89 http script var: "3"
2016/07/12 18:44:23 [debug] 3580#292: *89 http script regex end
2016/07/12 18:44:23 [notice] 3580#292: *89 rewritten redirect: "/bbs/#/7?cid=3", client: 127.0.0.1, server: localhost, request: "GET /topic/module/7?channel=3 HTTP/1.1", host: "localhost"
2016/07/12 18:44:23 [debug] 3580#292: *89 http finalize request: 301, "/topic/module/7?channel=3" a:1, c:1
2016/07/12 18:44:23 [debug] 3580#292: *89 http special response: 301, "/topic/module/7?channel=3"
2016/07/12 18:44:23 [debug] 3580#292: *89 http set discard body
2016/07/12 18:44:23 [debug] 3580#292: *89 HTTP/1.1 301 Moved Permanently
Server: nginx/1.10.1
Date: Tue, 12 Jul 2016 10:44:23 GMT
Content-Type: text/html
Content-Length: 185
Location: http://localhost/bbs/#/7?cid=3
Connection: keep-alive

2016/07/12 18:44:23 [debug] 3580#292: *89 write new buf t:1 f:0 0051896C, pos 0051896C, size: 205 file: 0, size: 0
2016/07/12 18:44:23 [debug] 3580#292: *89 http write filter: l:0 f:0 s:205
2016/07/12 18:44:23 [debug] 3580#292: *89 http output filter "/topic/module/7?channel=3"
2016/07/12 18:44:23 [debug] 3580#292: *89 http copy filter: "/topic/module/7?channel=3"
2016/07/12 18:44:23 [debug] 3580#292: *89 http postpone filter "/topic/module/7?channel=3" 00518B04
2016/07/12 18:44:23 [debug] 3580#292: *89 write old buf t:1 f:0 0051896C, pos 0051896C, size: 205 file: 0, size: 0
2016/07/12 18:44:23 [debug] 3580#292: *89 write new buf t:0 f:0 00000000, pos 00EC39D8, size: 132 file: 0, size: 0
2016/07/12 18:44:23 [debug] 3580#292: *89 write new buf t:0 f:0 00000000, pos 00EC3780, size: 53 file: 0, size: 0
2016/07/12 18:44:23 [debug] 3580#292: *89 http write filter: l:1 f:0 s:390
2016/07/12 18:44:23 [debug] 3580#292: *89 http write filter limit 0
2016/07/12 18:44:23 [debug] 3580#292: *89 WSASend: fd:400, s:390
2016/07/12 18:44:23 [debug] 3580#292: *89 http write filter 00000000
2016/07/12 18:44:23 [debug] 3580#292: *89 http copy filter: 0 "/topic/module/7?channel=3"
2016/07/12 18:44:23 [debug] 3580#292: *89 http finalize request: 0, "/topic/module/7?channel=3" a:1, c:1
2016/07/12 18:44:23 [debug] 3580#292: *89 set http keepalive handler
2016/07/12 18:44:23 [debug] 3580#292: *89 http close request
2016/07/12 18:44:23 [debug] 3580#292: *89 http log handler
2016/07/12 18:44:23 [debug] 3580#292: *89 free: 00518010, unused: 1022
2016/07/12 18:44:23 [debug] 3580#292: *89 free: 005211A0
2016/07/12 18:44:23 [debug] 3580#292: *89 hc free: 00000000 0
2016/07/12 18:44:23 [debug] 3580#292: *89 hc busy: 00000000 0
2016/07/12 18:44:23 [debug] 3580#292: *89 tcp_nodelay

上面提到的问题解决了，原因是如下：

2016/07/12 20:13:28 [debug] 4044#3764: *15 http process request line
2016/07/12 20:13:28 [debug] 4044#3764: *15 http request line: "GET /topic/module/7?channel=3 HTTP/1.1"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http uri: "/topic/module/7"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http args: "channel=3"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http exten: ""
2016/07/12 20:13:28 [debug] 4044#3764: *15 http process request header line
2016/07/12 20:13:28 [debug] 4044#3764: *15 http header: "Host: localhost"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http header: "Connection: keep-alive"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http header: "Upgrade-Insecure-Requests: 1"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http header: "User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.106 Safari/537.36"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http header: "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http header: "Accept-Encoding: gzip, deflate, sdch"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http header: "Accept-Language: zh-CN,zh;q=0.8"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http header done
2016/07/12 20:13:28 [debug] 4044#3764: *15 event timer del: 400: 3741821009
2016/07/12 20:13:28 [debug] 4044#3764: *15 generic phase: 0
2016/07/12 20:13:28 [debug] 4044#3764: *15 rewrite phase: 1
2016/07/12 20:13:28 [debug] 4044#3764: *15 test location: "/"
2016/07/12 20:13:28 [debug] 4044#3764: *15 test location: "api"
2016/07/12 20:13:28 [debug] 4044#3764: *15 test location: "topic/view"
2016/07/12 20:13:28 [debug] 4044#3764: *15 test location: ~ "/topic/module/\d+"
2016/07/12 20:13:28 [debug] 4044#3764: *15 using configuration "/topic/module/\d+"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http cl:-1 max:1048576
2016/07/12 20:13:28 [debug] 4044#3764: *15 rewrite phase: 3
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script var
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script var: "channel=3"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script regex: "channel=(\d+)"
2016/07/12 20:13:28 [notice] 4044#3764: *15 "channel=(\d+)" matches "channel=3", client: 127.0.0.1, server: localhost, request: "GET /topic/module/7?channel=3 HTTP/1.1", host: "localhost"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script if
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script regex: "/topic/module/(\d+)"
2016/07/12 20:13:28 [notice] 4044#3764: *15 "/topic/module/(\d+)" matches "/topic/module/7", client: 127.0.0.1, server: localhost, request: "GET /topic/module/7?channel=3 HTTP/1.1", host: "localhost"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script copy: "/bbs/#/"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script capture: "7"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script args
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script copy: "cid="
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script var: "3"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http script regex end
2016/07/12 20:13:28 [notice] 4044#3764: *15 rewritten data: "/bbs/#/7", args: "cid=3", client: 127.0.0.1, server: localhost, request: "GET /topic/module/7?channel=3 HTTP/1.1", host: "localhost"
2016/07/12 20:13:28 [debug] 4044#3764: *15 post rewrite phase: 4
2016/07/12 20:13:28 [debug] 4044#3764: *15 uri changes: 11
2016/07/12 20:13:28 [debug] 4044#3764: *15 test location: "/"
2016/07/12 20:13:28 [debug] 4044#3764: *15 test location: "api"
2016/07/12 20:13:28 [debug] 4044#3764: *15 test location: "topic/view"
2016/07/12 20:13:28 [debug] 4044#3764: *15 test location: ~ "/topic/module/\d+"
2016/07/12 20:13:28 [debug] 4044#3764: *15 using configuration "/"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http cl:-1 max:1048576
2016/07/12 20:13:28 [debug] 4044#3764: *15 rewrite phase: 3
2016/07/12 20:13:28 [debug] 4044#3764: *15 post rewrite phase: 4
2016/07/12 20:13:28 [debug] 4044#3764: *15 generic phase: 5
2016/07/12 20:13:28 [debug] 4044#3764: *15 generic phase: 6
2016/07/12 20:13:28 [debug] 4044#3764: *15 generic phase: 7
2016/07/12 20:13:28 [debug] 4044#3764: *15 access phase: 8
2016/07/12 20:13:28 [debug] 4044#3764: *15 access phase: 9
2016/07/12 20:13:28 [debug] 4044#3764: *15 access phase: 10
2016/07/12 20:13:28 [debug] 4044#3764: *15 post access phase: 11
2016/07/12 20:13:28 [debug] 4044#3764: *15 content phase: 12
2016/07/12 20:13:28 [debug] 4044#3764: *15 content phase: 13
2016/07/12 20:13:28 [debug] 4044#3764: *15 content phase: 14
2016/07/12 20:13:28 [debug] 4044#3764: *15 content phase: 15
2016/07/12 20:13:28 [debug] 4044#3764: *15 content phase: 16
2016/07/12 20:13:28 [debug] 4044#3764: *15 content phase: 17
2016/07/12 20:13:28 [debug] 4044#3764: *15 http filename: "D:/workspace/webapp/bbs/#/7"
2016/07/12 20:13:28 [debug] 4044#3764: *15 add cleanup: 00DF8948
2016/07/12 20:13:28 [error] 4044#3764: *15 CreateFile() "D:/workspace/webapp/bbs/#/7" failed (3: The system cannot find the path specified), client: 127.0.0.1, server: localhost, request: "GET /topic/module/7?channel=3 HTTP/1.1", host: "localhost"
2016/07/12 20:13:28 [debug] 4044#3764: *15 http finalize request: 404, "/bbs/#/7?cid=3" a:1, c:1
2016/07/12 20:13:28 [debug] 4044#3764: *15 http special response: 404, "/bbs/#/7?cid=3"
2016/07/12 20:13:28 [debug] 4044#3764: *15 internal redirect: "/404.html?"

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