ntpdate stdtime.gov.hk ; hwclock -w &> /dev/null
echo '01 03 * * * /usr/sbin/ntpdate stdtime.gov.hk' |tee -a /var/spool/cron/root? #同步系統(tǒng)時(shí)間

sed -i 's/^SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config? ? ? ? ? ? ? #關(guān)閉SELinux

sed -i 's/HISTSIZE=1000/HISTSIZE=200/' /etc/profile? ? ? ? ? ? ? ? ? ? ? ? ? ? ? #設(shè)置linux命令保存的條數(shù)

sed -i 's/^id:5:initdefault:/id:3:initdefault:/' /etc/inittab? ? ? ? ? ? ? ? ? ? #將linxu圖像模式改成命令模式

sed -i 's/4096/65535/' /etc/security/limits.d/20-nproc.conf? ? ? ? ? ? ?#設(shè)置linxu最大打開進(jìn)程數(shù)量

sed -i 's/^MAILTO=root/MAILTO=""/' /etc/crontab? ? ? ? ? ? ? ? ? ? ?#設(shè)置計(jì)劃任務(wù)的使用者為空（所以）

sed -i 's/^mail\.\*/mail\.err/' /etc/rsyslog.conf? ? ? ? ? ? ? ? ? ? ? ? ? ? ?#

echo 'HISTFILESIZE=4000' |tee -a /etc/bashrc &> /dev/null? ? ? ? ? ?#保存命令的記錄總數(shù)4000

echo 'HISTSIZE=4000' |tee -a /etc/bashrc &> /dev/null? ? ? ? #輸出history文件中的最后HISTSIZE行

echo 'HISTTIMEFORMAT=" `whoami` %F %T "' |tee -a /etc/bashrc &> /dev/null?
?#顯示命令的執(zhí)行時(shí)間，執(zhí)行者
echo 'ulimit -S -c 0 > /dev/null 2>&1 ' |tee -a /etc/profile &> /dev/null? ? ?
?#設(shè)置core文件大小為0，然后輸出信息以及錯(cuò)誤信息都不輸出在顯示器上

echo 'ulimit -s unlimited' |tee -a /etc/profile &> /dev/null? ? ? ? ? ? ? ? ? ? ? #設(shè)置堆棧大小

echo 'ulimit -SHn 65535' |tee -a /etc/profile &> /dev/null? ? ? ? ? ? ? ? ? ? ? ? #設(shè)置連接數(shù)最大值

echo '*? ? soft? ? nofile? 65535' |tee -a /etc/security/limits.conf &> /dev/null? #最大文件打開數(shù)優(yōu)化

echo '*? ? hard? ? nofile? 65535' |tee -a /etc/security/limits.conf &> /dev/null? #最大文件打開數(shù)優(yōu)化

echo '*? ? soft? ? nproc? 65535' |tee -a /etc/security/limits.conf &> /dev/null? #最大文件打開數(shù)優(yōu)化

echo '*? ? hard? ? nproc? 65535' |tee -a /etc/security/limits.conf &> /dev/null? #最大文件打開數(shù)優(yōu)化
以上是基本配置調(diào)優(yōu)，還有內(nèi)核參數(shù)的調(diào)優(yōu)
vim? /etc/sysctl.conf
net.ipv4.ip_forward = 1

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#開啟路由功能net.ipv4.conf.default.rp_filter = 1
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#禁用所有IP源路由net.ipv4.conf.default.accept_source_route = 0
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#禁用icmp源路由選項(xiàng)kernel.sysrq = 0
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#關(guān)閉SysRq功能，SysRq代表的是Magic System Request Key
kernel.core_uses_pid = 1
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#控制core文件的文件名是否添加pid作為擴(kuò)展
net.ipv4.tcp_syncookies = 1
#~~~~~~~~~~~~~~~~~~~~~~~~#默認(rèn)的每個(gè)消息隊(duì)列的最大尺寸（byte），默認(rèn)為16384
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
fs.file-max = 6553600
#~~~~~~~~~~~~~~~~~~~~~~~#系統(tǒng)級(jí)最大打開文件數(shù)，還要結(jié)合limits.conf的soft和hard限制net.ipv4.tcp_max_tw_buckets = 262144
net.ipv4.tcp_sack = 1
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#定義SYN重試次數(shù)net.ipv4.tcp_window_scaling = 1
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#開啟窗口縮放功能net.ipv4.tcp_rmem = 4096 87380 6291456

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#socket的發(fā)送緩存區(qū)分配的MIN，DEFAULT,MAX

net.core.netdev_max_backlog = 200000

net.core.somaxconn = 65535

net.core.wmem_default = 8388608

net.core.rmem_max = 16777216

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#表示套接字發(fā)送緩沖區(qū)大小的最大值,會(huì)覆蓋net.ipv4.tcp_wmem的MAX值

net.ipv4.tcp_timestamps = 0

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#禁用時(shí)間戳，時(shí)間戳可以避免序列號(hào)的卷繞

net.ipv4.tcp_synack_retries = 2

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#syn-ack握手狀態(tài)重試次數(shù)，默認(rèn)5，遭受syn-flood攻擊時(shí)改為1或2

net.ipv4.tcp_syn_retries = 2

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#外向syn握手重試次數(shù)，默認(rèn)4

net.ipv4.tcp_tw_recycle = 1

net.ipv4.tcp_tw_reuse = 1

net.ipv4.tcp_mem = 3097431 4129911 6194862

net.ipv4.tcp_max_orphans = 3276800

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#選項(xiàng)用于設(shè)定系統(tǒng)中最多有多少個(gè)TCP套接字不被關(guān)聯(lián)到任何一個(gè)用戶文件

句柄上，

net.ipv4.tcp_fin_timeout = 2

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#修改系統(tǒng)默認(rèn)的 TIMEOUT 時(shí)間

net.ipv4.tcp_keepalive_time = 30

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#表示當(dāng)keepalive起用的時(shí)候，TCP發(fā)送keepalive消息的頻度。缺省是2小>時(shí)，改為5分鐘。

net.ipv4.ip_local_port_range = 1024 65535

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#表示用于向外連接的端口范圍。缺省情況下過窄：32768到61000，改為1024到65535

#vm.overcommit_memory = 1

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#設(shè)置redis,內(nèi)存模式

net.nf_conntrack_max = 25000000

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#增大iptables狀態(tài)跟蹤表

net.ipv4.conf.all.arp_notify = 1
vm.swappiness = 5

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#100-1=99%內(nèi)存時(shí)才使用swap

net.netfilter.nf_conntrack_max = 25000000
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#設(shè)置默認(rèn) TCP 連接時(shí)長為180秒，Iptables

net.netfilter.nf_conntrack_tcp_timeout_established = 180
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#設(shè)置默認(rèn) TCP 連接時(shí)長為180秒，Iptables
#modprobe nf_conntrack

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