记个Apache汉语言手册地址（负载均衡配置及会话保持配置说明）

ProxyPass 指令

该指令允许你将一个远端服务器映射到本地服务器的URL空间中，此时本地服务器并不充当代理角色，而是充当远程服务器的一个镜像。path是一个本地虚拟路径名，url是一个指向远程服务器的部分URL，并且不允许包含查询字符串。

当使用
ProxyPass指令时，
ProxyRequests指令通常应当被设为
off 。

假设本地服务器地址是：http://example.com/ ，那么，

ProxyPass /mirror/foo/ http://backend.example.com/

将会导致对http://example.com/mirror/foo/bar的本地请求将会在内部转换为一个代理请求：http://backend.example.com/bar 。

“!“指令对于您不想对某个子目录进行反向代理时很有用。比如说：

ProxyPass /mirror/foo/i !
ProxyPass /mirror/foo http://backend.example.com

将会代理除/mirror/foo/i之外的所有对backend.example.com下/mirror/foo的请求。

注意

顺序很重要，您需要把拒绝指令放置在普通ProxyPass指令之前。

As of Apache 2.1, the ability to use pooled connections to a backend server is available. Using the key=value parameters it is possible to tune this connection pooling. The default for a Hard Maximum for the number of connections is the number of threads per process in the active MPM. In the Prefork MPM, this is always 1, while with the Worker MPM it is controlled by the ThreadsPerChild.

Setting min will determine how many connections will always be open to the backend server. Upto the Soft Maximum or smax number of connections will be created on demand. Any connections above smax are subject to a time to live or ttl. Apache will never create more than the Hard Maximum or max connections to the backend server.

ProxyPass /example http://backend.example.com smax=5 max=20 ttl=120 retry=300