阿里云的slb ，开启健康检测通常会发大量的HEAD 请求过来，这些日志需要屏蔽。步骤如下：
shell>service httpd restart
- Remote_Host: the hostname (if available) of the client making the request.
- Remote_Addr: the IP address of the client making the request.
- Server_Addr: the IP address of the server on which the request was received (only with versions later than 2.0.43).
- Request_Method: the name of the method being used (GET, POST, etc.).
- Request_Protocol: the name and version of the protocol with which the request was made (e.g., “HTTP/0.9”, “HTTP/1.1”, etc.).
- Request_URI: the resource requested on the HTTP request line – generally the portion of the URL following the scheme and host portion without the query string.