Linux内核参数调优主要是通过改削/proc伪文件系统和/etc/sysctl.conf配置文件的参数来实现的。
/proc目录布局如下：
/proc/driver        与驱动器相关的信息
/proc/fs            文件系统参数
/proc/net           网络信息
/proc/pid           每个进程的信息
/proc/sys           内核参数
/proc/scsi          与scsi相关的信息
/proc/sys/kernel    通用内核参数
/proc/sys/vm        内存打点参数
/proc/sys/dev       与设备相关的信息
/proc/sys/net       网络信息

vim /etc/sysctl.conf
net.ipv4.tcp_syncookies = 1            #开启SYN Cookies。可以防止少量的SYN打击。
net.ipv4.ip_local_port_range = 10000 65535 #设置向外连接的端口范畴
net.ipv4.route.gc_timeout = 100        #路由缓存刷新频率
net.core.netdev_max_backlog = 16384    #允许排队更多的报文
net.core.somaxconn = 16384             #指定更大的accept行列队伍backlog
net.ipv4.tcp_max_syn_backlog = 16384   #增加SYN行列队伍长度
net.ipv4.tcp_synack_retries = 1        #从头发送响应的次数
net.ipv4.tcp_retries2 = 5              #向长途主机从头发送数据的次数
net.ipv4.tcp_keepalive_time = 1200     #内核向长途主机发送Keepalive动静的频度
net.ipv4.tcp_keepalive_intvl = 30      #内核向长途主机发送探测动静的间隔

系统优化脚本：

#!/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/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config 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 << EOF net.ipv4.tcp_syncookies = 1 net.ipv4.ip_local_port_range = 10000 65535 net.ipv4.route.gc_timeout = 100 net.core.netdev_max_backlog = 16384 net.core.somaxconn = 16384 net.ipv4.tcp_max_syn_backlog = 16384 net.ipv4.tcp_synack_retries = 1 net.ipv4.tcp_retries2 = 5 net.ipv4.tcp_keepalive_time = 1200 net.ipv4.tcp_keepalive_intvl = 30 EOF /sbin/sysctl -p for i in `chkconfig | grep 3:on | awk '{print $1}'` do chkconfig --level 3 $i off done for service in crond rsyslog sshd network do chkconfig --level 3 $service on done reboot