linux的基础优化(期中架构方面的优化)

• 1. linux内核优化

  第一步

  cat >>/etc/sysctl.conf<<EOF
  net.ipv4.tcp_fin_timeout = 2
  net.ipv4.tcp_tw_reuse = 1
  net.ipv4.tcp_tw_recycle = 1
  net.ipv4.tcp_syncookies = 1
  net.ipv4.tcp_keepalive_time = 600
  net.ipv4.ip_local_port_range = 4000 65000
  net.ipv4.tcp_max_syn_backlog = 16384
  net.ipv4.tcp_max_tw_buckets = 36000
  net.ipv4.route.gc_timeout = 100
  net.ipv4.tcp_syn_retries = 1
  net.ipv4.tcp_synack_retries = 1
  net.core.somaxconn = 16384
  net.core.netdev_max_backlog = 16384
  net.ipv4.tcp_max_orphans = 16384
  iptables
  net.nf_conntrack_max = 25000000
  net.netfilter.nf_conntrack_max = 25000000
  net.netfilter.nf_conntrack_tcp_timeout_established = 180
  net.netfilter.nf_conntrack_tcp_timeout_time_wait = 120
  net.netfilter.nf_conntrack_tcp_timeout_close_wait = 60
  net.netfilter.nf_conntrack_tcp_timeout_fin_wait = 120
  EOF
  

  第二步：

  sysctl -p

  
  
  
  

• 2. 添加双网卡需要激活

  

• 3. 关闭防火墙(2步)

  sed -i 's#SELINUX=enforcing#SELINUX=disabled#g' /etc/selinux/config
  /etc/init.d/iptables stop

• 4. 时间同步服务(2步)

  \ntpdate -u cn.pool.ntp.org
  hwclock -w \写入硬件时间
  hwclock -r \查看当前硬件时间
  

  
  配置时间同步任务
  yum -y install ntp \安装时间同步工具
  

  
  2. 同步时间的两种方法
  -1.开机同步
  vim /etc/rc.d/rc.local
  /usr/sbin/ntpdate -u cn.pool.ntp.org >/dev/null 2>&1; /sbin/hwclock -w
  

  
  -2.定时任务同步
  vi /etc/crontab
  00 10 * * * root /usr/sbin/ntpdate -u cn.pool.ntp.org >/dev/null 2>&1; /sbin/hwclock -w #(更新时间同时写入硬件)

• 5.配置yum源添加eper源

  更换yum源
  -1. 清除yum源缓存
  yum clean all
  -2.备份yum源
  mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
  -3.更换 centos 7源
  下载新的源: wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
  -4.生成缓存
  yum makecahe
  5.添加epel源
  wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo

• 6.精简开机自启动

  chkconfig|egrep -v "crond|sshd|network|rsyslog|sysstat"|awk '{print "chkconfig",$1,"off"}'|bash

• 7.字符集更改

  cp /etc/sysconfig/i18n /etc/sysconfig/i18n.ori
  echo 'LANG="en_US.UTF-8"' >/etc/sysconfig/i18n
  source /etc/sysconfig/i18n
  echo $LANG

• 8.历史命令,断开时间优化

  echo 'export TMOUT=300' >>/etc/profile
  echo 'export HISTSIZE=5' >>/etc/profile
  echo 'export HISTFILESIZE=5' >>/etc/profile
  tail -3 /etc/profile
  . /etc/profile

• 9.下载安装系统基础软件

  yum install lrzsz nmap tree dos2unix nc -y

• 10.配置hosts文件(非优化项目,仅为实验)

  cat >/etc/hosts<<EOF
  127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
  ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
  172.16.1.5 lb01
  172.16.1.6 lb02
  172.16.1.7 web01
  172.16.1.8 web02
  172.16.1.9 web03
  172.16.1.51 db01
  172.16.1.31 nfs01
  172.16.1.41 backup
  172.16.1.61 m01
  172.16.1.62 jumpserver
  EOF