Linux tcp_tw_reuse 与 tcp_tw_recycle ：使用哪个（或两者）？
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tcp_tw_reuse vs tcp_tw_recycle : Which to use (or both)?
提问by Michael Marsee
I have a website and application which use a significant number of connections. It normally has about 3,000 connections statically open, and can receive anywhere from 5,000 to 50,000 connection attempts in a few seconds time frame.
我有一个使用大量连接的网站和应用程序。它通常静态打开大约 3,000 个连接，并且可以在几秒钟的时间内接收 5,000 到 50,000 次连接尝试。
I have had the problem of running out of local ports to open new connections due to TIME_WAIT status sockets. Even with tcp_fin_timeout set to a low value (1-5), this seemed to just be causing too much overhead/slowdown, and it would still occasionally be unable to open a new socket.
由于 TIME_WAIT 状态套接字，我遇到了用完本地端口来打开新连接的问题。即使将 tcp_fin_timeout 设置为较低的值 (1-5)，这似乎只会导致过多的开销/速度减慢，并且偶尔仍无法打开新套接字。
I've looked at tcp_tw_reuse and tcp_tw_recycle, but I am not sure which of these would be the preferred choice, or if using both of them is an option.
我已经查看了 tcp_tw_reuse 和 tcp_tw_recycle，但我不确定其中哪一个是首选，或者是否可以选择同时使用它们。
回答by Cédric Julien
According to Linux documentation, you should use the TCP_TW_REUSE flag to allow reusing sockets in TIME_WAIT state for new connections.
根据Linux 文档，您应该使用 TCP_TW_REUSE 标志来允许将 TIME_WAIT 状态的套接字重用于新连接。
It seems to be a good option when dealing with a web server that have to handle many short TCP connections left in a TIME_WAIT state.
在处理必须处理许多处于 TIME_WAIT 状态的短 TCP 连接的 Web 服务器时，这似乎是一个不错的选择。
As described here, The TCP_TW_RECYCLE could cause some problems when using load balancers...
如上所述这里，该TCP_TW_RECYCLE可以使用负载均衡器时，会导致一些问题...
EDIT (to add some warnings ;) ):
编辑（添加一些警告;））：
as mentionned in comment by @raittes, the "problems when using load balancers" is about public-facing servers. When recycle is enabled, the server can't distinguish new incoming connections from different clients behind the same NAT device.
正如@raittes 在评论中提到的，“使用负载均衡器时的问题”是关于面向公众的服务器。启用回收后，服务器无法区分来自同一 NAT 设备后面的不同客户端的新传入连接。
回答by pevik
NOTE: net.ipv4.tcp_tw_recyclehas been removedfrom Linux?4.12.
注：net.ipv4.tcp_tw_recycle已被删除？从Linux的4.12。
SOURCE: https://vincent.bernat.im/en/blog/2014-tcp-time-wait-state-linux
来源：https: //vincent.bernat.im/en/blog/2014-tcp-time-wait-state-linux
