modifying Linux kernel parameters to improve the performance of Nginx servers in high concurrency

Concurrent Linux under the high concurrency of the Nginx server, when the TCP time_wait socket number often reached 20,000 or 30,000, the server is easily towed to death. By modifying the Linux kernel parameters, you can reduce the number of time_wait sockets for the Nginx server.

Vi/etc/sysctl.conf

Add the following lines:

Reference

Net.ipv4.tcp_fin_timeout = 30

Net.ipv4.tcp_keepalive_time = 1200

Net.ipv4.tcp_syncookies = 1

Net.ipv4.tcp_tw_reuse = 1

Net.ipv4.tcp_tw_recycle = 1

Net.ipv4.ip_local_port_range = 1024 65000

Net.ipv4.tcp_max_syn_backlog = 8192

Net.ipv4.tcp_max_tw_buckets = 5000

Simple description:

Net.ipv4.tcp_syncookies = 1 means to open syn Cookies. When the SYN wait queue overflow occurs, cookies are enabled to handle, to prevent a small number of SYN attacks, the default is 0, indicating shutdown;

Net.ipv4.tcp_tw_reuse = 1 means to turn on reuse. Allows time-wait sockets to be re used for a new TCP connection, which defaults to 0, indicating shutdown;

Net.ipv4.tcp_tw_recycle = 1 is a quick recycle of time-wait sockets on a TCP connection, and the default is 0, which means shutdown.

Net.ipv4.tcp_fin_timeout = 30 indicates that if the socket is closed by the local end, this parameter determines how long it remains in the fin-wait-2 state.

Net.ipv4.tcp_keepalive_time = 1200 means the frequency at which TCP sends keepalive messages when KeepAlive is enabled. The default is 2 hours, and 20 minutes instead.

Net.ipv4.ip_local_port_range = 1024 65000 indicates the range of ports used for outward joins. Small by default: 32768 to 61000, 1024 to 65000.

Net.ipv4.tcp_max_syn_backlog = 8192 Indicates the length of the SYN queue, the default is 1024, and the queue length is 8192, which can accommodate more network connections waiting for connections.