CentOS 6 系统优化 Shell 脚本(转)

CentOS 已经发布了6.2版了，现在已经可以用在生产环境了，新版本的内核也能更好的利用硬件。写了一个脚本，用来初始化系统环境，现在分享出来，你可以根据自己的需要，对脚本进行相应的修改。

脚本的内容如下：

#!/bin/bash
#author suzezhi
#this script is only for CentOS 6
#check the OS

platform=`uname -i`
if [ $platform != "x86_64" ];then
echo "this script is only for 64bit Operating System !"
exit 1
fi
echo "the platform is ok"
version=`lsb_release -r |awk '{print substr($2,1,1)}'`
if [ $version != 6 ];then
echo "this script is only for CentOS 6 !"
exit 1
fi
cat << EOF
+---------------------------------------+
|   your system is CentOS 6 x86_64      |
|      start optimizing.......          |
+---------------------------------------
EOF

#make the 163.com as the default yum repo
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
wget -O /etc/yum.repos.d/CentOS-Base.repo

#add the third-party repo
#add the epel
rpm -Uvh
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

#add the rpmforge
rpm -Uvh
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-dag

#update the system and set the ntp
yum clean all
yum -y update glibc\*
yum -y update yum\* rpm\* python\*
yum -y update
yum -y install ntp
echo "* 4 * * * /usr/sbin/ntpdate 210.72.145.44 > /dev/null 2>&1" >> /var/spool/cron/root
service crond restart

#set the file limit
echo "ulimit -SHn 102400" >> /etc/rc.local
cat >> /etc/security/limits.conf << EOF
*           soft   nofile       65535
*           hard   nofile       65535
EOF

#set the control-alt-delete to guard against the miSUSE
sed -i 's#exec /sbin/shutdown -r now#\#exec /sbin/shutdown -r now#' /etc/init/control-alt-delete.conf

#disable selinux
sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config

#set ssh
sed -i 's/^GSSAPIAuthentication yes$/GSSAPIAuthentication no/' /etc/ssh/sshd_config
sed -i 's/#UseDNS yes/UseDNS no/' /etc/ssh/sshd_config
service sshd restart

#tune kernel parametres
cat >> /etc/sysctl.conf << EOF
net.ipv4.tcp_fin_timeout = 1
net.ipv4.tcp_keepalive_time = 1200
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_tw_recycle = 1
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.netdev_max_backlog = 262144
net.core.somaxconn = 262144
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_max_syn_backlog = 262144
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
EOF
/sbin/sysctl -p

#define the backspace button can erase the last character typed
echo 'stty erase ^H' >> /etc/profile
echo "syntax on" >> /root/.vimrc

#stop some crontab
mkdir /etc/cron.daily.bak
mv /etc/cron.daily/makewhatis.cron /etc/cron.daily.bak
mv /etc/cron.daily/mlocate.cron /etc/cron.daily.bak
chkconfig bluetooth off
chkconfig cups off
chkconfig ip6tables off
#disable the ipv6
cat > /etc/modprobe.d/ipv6.conf << EOFI
alias net-pf-10 off
options ipv6 disable=1
EOFI
echo "NETWORKING_IPV6=off" >> /etc/sysconfig/network
cat << EOF
+-------------------------------------------------+
|               optimizer is done                 |
|   it's recommond to restart this server !       |
+-------------------------------------------------+
EOF

对脚本的内容做一下说明：

    先对系统进行判断，如果是Cent OS 64位，就继续运行。
    先将系统的安装源设置为网易的（网易的安装源算是国内比较稳定的）
    安装epel的源和rpmforge的源，利用第三方的源来让yum安装起来更方便
    更新软件
    设置为每天凌晨四点进行时间同步（跟国家授时中心的服务器进行时间同步）
    将系统同时打开的文件个数增大
    将ctrl ALT delete键进行屏蔽，防止误操作的时候服务器重启
    关闭SELinux
    禁用GSSAPI来认证，也禁用DNS反向解析，加快SSH登陆速度
    优化一些内核参数
    调整删除字符的按键为backspace（某些系统默认是delete）
    打开vim的语法高亮
    取消生成whatis数据库和locate数据库
    关闭没用的服务
    关闭IPv6  

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