CentOS 6 系統優化 Shell 腳本

CentOS 已經發布了6.2版了，現在已經可以用在生產環境了，新版本的內核也能更好的利用硬件。寫了一個腳本，用來初始化系統環境，現在分享出來，你可以根據自己的需要，對腳本進行相應的修改。

腳本的內容如下： 

#!/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 http://mirrors.163.com/.help/CentOS6-Base-163.repo -O /etc/yum.repos.d/CentOS-Base.repo

#add the third-party repo
#add the epel
rpm -Uvh http://download.Fedora.RedHat.com/pub/epel/6/x86_64/epel-release-6-5.noarch.rpm
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

#add the rpmforge
rpm -Uvh http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm
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

對腳本的內容做一下說明：

1. 先對系統進行判斷，如果是Cent OS 64位，就繼續運行。
2. 先將系統的安裝源設置為網易的（網易的安裝源算是國內比較穩定的）
3. 安裝epel的源和rpmforge的源，利用第三方的源來讓yum安裝起來更方便
4. 更新軟件
5. 設置為每天凌晨四點進行時間同步（跟國家授時中心的服務器進行時間同步）
6. 將系統同時打開的文件個數增大
7. 將ctrl ALT delete鍵進行屏蔽，防止誤操作的時候服務器重啟
8. 關閉SELinux
9. 禁用GSSAPI來認證，也禁用DNS反向解析，加快SSH登陸速度
10. 優化一些內核參數
11. 調整刪除字符的按鍵為backspace（某些系統默認是delete）
12. 打開vim的語法高亮
13. 取消生成whatis數據庫和locate數據庫
14. 關閉沒用的服務
15. 關閉IPv6