A good parameter to the kernel in Linux Somaxconn

Introduction: In Linux,/proc/sys/net/core/somaxconn this parameter, a good parameter of the kernel in Linux Somaxconn

Look at its parsing:

For a TCP connection, the server and client need to have a three-time handshake to establish a network connection. When the three-time handshake succeeds,

We can see that the status of the port is changed from listen to established, and then the link can start transmitting data.

Each port in the listening (Listen) state has its own listening queue. The length of the listening queue is related to the following two aspects:

-Somaxconn parameters.

-The Listen () function in the program that uses the port.

1. About Somaxconn Parameters:

Defines the length of the maximum listening queue for each port in the system, which is a global parameter with a default value of 1024, with the following information:

Purpose:

Specifies the maximum listen backlog.

Values:

default:1024 connections

range:0 to Maxshort

Type:connect

Diagnosis:

N/A

Tuning

Increase this parameter in busy WEB servers to handle peak connection rates.

Look at the analysis of FreeBSD:

Limits the size of the listening queue to receive new TCP connections. The default of 128 is too small for a high-load Web service environment that often handles new connections. Most environments this value is recommended to increase to 1024 or more. The service process itself limits the size of the listening queue (for example, SendMail (8) or Apache), and often has the option to set the queue size in their configuration file. A large listening queue can also help prevent denial-of-service DoS attacks.

Modify Somaxconn

The default value for this kernel parameter is typically 128, which is not large enough for a heavily loaded service program. It is generally modified to be 2048 or larger.

echo 2048 >/proc/sys/net/core/somaxconn But it won't save after the system restarts.

Add the following in the/etc/sysctl.conf

Net.core.somaxconn = 2048

And then execute it in the terminal.

Sysctl-p

Reprint: http://www.233.com/linux/fudao/20100716/102722174.html

A good parameter to the kernel in Linux Somaxconn