nginx学习笔记0

今天正式开始学习nginx，nginx以前是接触过，不过都是照着教程来的，今天一定要好好学一下！

我将分好几次分别记录我学习nginx的历程。

本文参考马哥的nginx教程而写的笔记

http://news.netcraft.com/
这个是一个统计当前web服务器的各种信息的网站!

由上图可知，nginx稳坐第三名，群众的眼睛都是雪亮的！nginx会超过微软的IIS！

http://nginx.org/ 官方网站
nginx采用epoll事件模型（内核2.6以上支持！），I/O效率相当高！（Apache采用select机制，稳定）
具体为什么可以参看
http://www.cppblog.com/converse/archive/2008/10/12/63836.html
http://xinlogs.com/nginx-epool-events

nginx [engine x] is anHTTP and reverse proxy server,as well as a mail proxy server, written byIgor Sysoev. For a long time, it has been runningon many heavily loaded Russian sites includingYandex,Mail.Ru,VKontakte, andRambler. According to Netcraft nginx served orproxied10.09% busiest sites in April 2012. Here are someof the success stories:FastMail.FM,Wordpress.com.

读法，enginex 貌似我一直都读错的，擦泪！HTTP服务器，反向代理（proxy）服务器,邮件反向代理，是个俄罗斯人写的，单台nginx服务器可以处理时5万个并发，Apache最多只能处理3000个，但是Apache稳定且功能众多，所以nginx做了众多网站的反向代理服务器，作为负载均衡，咱们精弘网络也是Apache做后台，tomcat处理jsp，而nginx处理静态页面！

The sources are distributed under the2-clause BSD-likelicense.
Basic HTTP server features
Serving static and index files, andautoindexing;open file descriptor cache;

处理静态主页，自动索引，作为文件描述符的缓存，这样再次访问特别快！
Accelerated reverse proxying with caching;simple load balancing and fault tolerance;
用cache加速反向代理！（这里可以对比一下squid服务！squid与apache相同属于重量级的反向代理，一次相对有varnish这款缓存在内存中的！）

Accelerated support with caching ofFastCGI, uwsgi, SCGI, andmemcached servers;simple load balancing and fault tolerance;

memcached是分布式的内存缓存服务器！fastcgi（php）uwsgi（python）nginx本身的缓存机制不如varnish等，varnish与squid的缓存能力很强！而nginx对于HTTP请求的处理能力很强！通常的架构一般是这样的：前端nginx只做反向代理处理HTTP请求，不做任何缓存。后端直接指向varnish或squid做为缓存，在后面是Apache实现web应用！所以没有一种超级NB的服务软件的把所有事都给干了，所以想要有市场份额，你就必须有超出其他服务的特长！做人亦如此！

Modular architecture. （模块化）Filters includegzipping, byte ranges, chunked responses,XSLT,SSI, andimage transformation filter. Multiple SSIinclusions within a single page can be processed in parallel if they arehandled by proxied or FastCGI servers;
SSL and TLS SNI support.

淘宝使用nginx，但是对于淘宝这么夸张的pv数，nginx某些时候不够用，淘宝就针对这个再做了一个tengine的web服务器！
官网如下，http://tengine.taobao.org/index_cn.html （tengine是开源产品哦！来自淘宝核心系统开发部门，让偶想起了上次的OceanBase！）

Other HTTP server features
Name-based and IP-basedvirtual servers;

基于域名或者IP的虚拟主机

Keep-alive and pipelined connectionssupport;
Flexible configuration;
Reconfiguration andupgradeof an executable without interruption of the client servicing;

重写配置，可以不打断当前用户请求

Access log formats,buffered log writing, andfastlog rotation;

日志格式，可以缓存日志！（日志会涉及磁盘读写，可以先缓存，在一次写入，提高磁盘效率），支持快速日志滚动！

3xx-5xx error codesredirection;

自定义错误页面，我们的404,500等错误页面

The rewrite module:URI changing using regular expressions;

重写模块，URI（同一资源定位符）
根据url，域名的不同，将http请求发到不同的服务器分组

Executing different functions depending ontheclient address;

基于客户端地址的不同执行不同的功能模块

Access control based onclient IP address andHTTP Basic authentication;
Validation ofHTTP referer;
ThePUT, DELETE, MKCOL, COPY, and MOVE methods;
FLV andMP4 streaming;

各种流媒体视频格式

Response rate limiting;

响应速度限制，例如：凡是来自于上海的IP响应为5K/s,杭州的500K/s

Limiting the number of simultaneousconnections orrequests coming from one address;

Embedded Perl.

可以启用Perl（啊!）

Mail proxy server features
User redirection to IMAP/POP3 backend using an external HTTP authenticationserver;
User authentication using an external HTTP authentication server and connectionredirection to an internal SMTP backend;

Authentication methods:

POP3: USER/PASS, APOP, AUTH LOGIN/PLAIN/CRAM-MD5;

IMAP: LOGIN, AUTH LOGIN/PLAIN/CRAM-MD5;

SMTP: AUTH LOGIN/PLAIN/CRAM-MD5;

SSL support;

STARTTLS and STLS support.

Architecture and scalability

One master and several worker processes; worker processes run under an unprivileged user;

The notification methods: kqueue (FreeBSD 4.1+), epoll (Linux 2.6+), rt signals (Linux 2.2.19+), /dev/poll (Solaris 7 11/99+), event ports (Solaris 10), select, and poll;

各种机制，你说咋就没Windows呢？！

The support of the various kqueue features including EV_CLEAR, EV_DISABLE (to temporarily disable events), NOTE_LOWAT, EV_EOF, number of available data, error codes;

sendfile (FreeBSD 3.1+, Linux 2.2+, Mac OS X 10.5+), sendfile64 (Linux 2.4.21+), and sendfilev (Solaris 8 7/01+) support;

啥叫sendfile？用户空间与内核空间的切换！

File AIO

(FreeBSD 4.3+, Linux 2.6.22+);

DIRECTIO

(FreeBSD 4.4+, Linux 2.4+, Solaris 2.6+, Mac OS X);

Accept-filters (FreeBSD 4.1+) and TCP_DEFER_ACCEPT (Linux 2.4+)support;

10,000 inactive HTTP keep-alive connections take about 2.5M memory;

10000的HTTP在线请求仅占用2.5M内存！

Data copy operations are kept to a minimum.

Tested OS and platforms

FreeBSD 3 — 10 / i386; FreeBSD 5 — 10 / amd64;

Linux 2.2 — 3 / i386; Linux 2.6 — 3 / amd64;

Solaris 9 / i386, sun4u; Solaris 10 / i386, amd64, sun4v;

AIX 7.1 / powerpc

Mac OS X / ppc, i386;

Windows XP, Windows Server 2003.

虽然上面讲了这么多，但nginx并非牛上了天，要不然Apache也不是老大哥！
源码安装咱直接省略了（最新的1.2稳定版在4.23放出！）
关于memcached，这块需要好好学习！
memcached注意与memcache的区别，一个d哦！咱php的memcache是php的API！（重要哦）

各个语言都有各自的memcached客户端！
nginx也有memcached的客户端
大型web解决方案可以还有
CDN加速！（contentdelivery network）

智能DNS（DNSPOD，dns.la）

关于nginx的配置文件，请参考我其他的nginx系列学习笔记。

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