Optimization of kernel parameters of Linux server

Linux kernel parameter tuning is mainly achieved by modifying the parameters of the / proc pseudo file system and / etc/sysctl.conf configuration file.

The directory structure of / proc is as follows:

/ proc/driver drive-related information

/ proc/fs file system parameters

/ proc/net network information

/ proc/pid information for each process

/ proc/sys kernel parameters

/ proc/scsi information related to scsi

/ proc/meminfo memory related information

/ proc/cpuinfo CPU related information

/ proc/loadavg system load

Modules or drivers loaded by / proc/modules system

/ proc/partitions system partition information

/ proc/version kernel version information

/ proc/stat CPU utilization, disk, memory page

/ proc/devices list of available devices

/ proc/sys/kernel general kernel parameters

/ proc/sys/vm memory management parameters

/ proc/sys/dev device-related information

/ proc/sys/net network information

The files in a process directory are described as follows:

File descriptor opened by the / proc/pid/fd process

Executable file for / proc/pid/exe process

/ proc/pid/cmdline some parameters of the current process running

/ proc/pid/environ the environment variable of the current process

/ proc/pid/status the basic status of the current process

Vim / etc/sysctl.conf

Net.ipv4.tcp_syncookies = 1 # enable SYN Cookies. Can prevent a small amount of SYN***.

Net.ipv4.ip_local_port_range = 10000 65535 # set the port range for outbound connections

Net.ipv4.route.gc_timeout = 100 # Route cache refresh frequency

Net.core.netdev_max_backlog = 16384 # allow queuing for more messages

Net.core.somaxconn = 16384 # specify a larger accept queue backlog

Net.ipv4.tcp_max_syn_backlog = 16384 # increase the length of the SYN queue

Net.ipv4.tcp_synack_retries = 1 # number of times to resend the response

Net.ipv4.tcp_retries2 = 5 # number of times to resend data to the remote host

Net.ipv4.tcp_keepalive_time = 1200 # how often the kernel sends Keepalive messages to remote hosts

Net.ipv4.tcp_keepalive_intvl = 30 # interval at which the kernel sends probe messages to remote hosts

System optimization script:

#! / bin/bash

Yum-y groupinstall "Development tools"

Cd / usr/local/src

Wget https://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

Rpm-ivh epel-release-6-8.noarch.rpm

Sed-I's etc/selinux/config SelinuxplenforcingAccording to SELINUXAfter

Sed-I 's/start on control-alt-delete/#start on control-alt-delete/' / etc/init/control-alt-delete.conf

Sed-I 's@exec / sbin/shutdown-r now "Control-Alt-Delete pressed" @ # exec / sbin/shutdown-r now "Control-Alt-Delete pressed" @' / etc/init/control-alt-delete.conf

Service iptables stop

Chkconfig iptables off

Ulimit-SHn 65534

Echo "ulimit-SHn 65534" > > / etc/rc.local

Cat > > / etc/sysctl.conf