nginx的location怎么设置匹配前后台地址？

我的配置：

server {
listen      80;
server_name     www.xxx.com xxx.com;



# server_name_in_redirect off;

root  /alidata/www/default/yooao/frontend/web;

location ~ \.php$ {

        fastcgi_pass   127.0.0.1:9000;
        fastcgi_index  index.php;
        fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
        include        fastcgi_params;
   }

location / {
index index.php ;
root  /alidata/www/default/yooao/frontend/web;
}

location ~ ^/backend$ {
index index.php ;
root  /alidata/www/default/yooao/backend/web;
}

}

现在是前台可以进去，后台却不对，我用的是yii2框架。之前没加

`location ~ \.php$ {
        fastcgi_pass   127.0.0.1:9000;
        fastcgi_index  index.php;
        fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
        include        fastcgi_params;
   }`

时进前台首页会变成下载页面。现在我想匹配url进后台不知道该怎么做了，现在进后台www.xxx.com/backend显示404,新手求指教

---

1. 官网文档明确给出如何配置 nginx，地址是：http://www.getyii.com/doc-2.0/guide/start-installation.html#nginx

2. 如果你使用的是高级版，项目初始化完成之后，frontend，backend 需要分别配置，即要配置两个vhost