1、关闭selinux
sed –I ‘s#SELINUX=enforcing#SELINUX=disabled#g’ /etc/selinux/config grep SELINUX=disabled /etc/selinux/config setenforce 0
2、关闭iptables
[root@backup-41 ~]# /etc/init.d/iptables stop [root@backup-41 ~]# chkconfig iptables stop [root@backup-41 ~]# chkconfig iptables off
3、精简开机自启动
[root@backup-41 ~]# chkconfig|egrep -v "crond|sshd|network|rsynclog|sysstat" |awk '{print "chkconfig",$1,"off"}'|bash [root@backup-41 ~]# LANG=en [root@backup-41 ~]# chkconfig --list|grep 3:on crond 0:off 1:off 2:on 3:on 4:on 5:on 6:off network 0:off 1:off 2:on 3:on 4:on 5:on 6:off sshd 0:off 1:off 2:on 3:on 4:on 5:on 6:off sysstat 0:off 1:on 2:on 3:on 4:on 5:on 6:off
4、添加sudo提权
[root@backup-41 ~]# useradd pyrene [root@backup-41 ~]# cp /etc/sudoers /etc/sudoers.ori [root@backup-41 ~]# echo "pyrene ALL=(ALL) NOPASSWD:ALL" >>/etc/sudoers #includedir /etc/sudoers.d pyrene ALL=(ALL) NOPASSWD:ALL [root@backup-41 ~]# tail -1 /etc/sudoers pyrene ALL=(ALL) NOPASSWD:ALL [root@backup-41 ~]# visudo -c /etc/sudoers: parsed OK
5、时间同步
[root@backup-41 ~]# [root@backup-41 ~]# echo '#time sync by pyrene at 2016-10-1' >>/var/spool/cron/root [root@backup-41 ~]# echo '*/5 * * * * /usr/sbin/ntpdate time.nist.gov >/dev/null 2>&1' >>/var/spool/cron/root [root@backup-41 ~]# crontab -l #time sync by pyrene at 2016-10-1 */5 * * * * /usr/sbin/ntpdate time.nist.gov >/dev/null 2>&1
6、加大文件描述符
[root@backup-41 ~]# echo '* - nofile 65535' >>/etc/security/limits.conf [root@backup-41 ~]# tail -1 /etc/security/limits.conf * - nofile 65535
7、内核优化
cat >>/etc/sysctl.conf<<EOF # 内核panic时,1秒后自动重启 kernel.panic = 1 # 允许更多的PIDs (减少滚动翻转问题); may break some programs 32768 kernel.pid_max = 32768 # 内核所允许的最大共享内存段的大小(bytes) kernel.shmmax = 4294967296 # 在任何给定时刻,系统上可以使用的共享内存的总量(pages) kernel.shmall = 1073741824 # 设定程序core时生成的文件名格式 kernel.core_pattern = core_%e # 当发生oom时,自动转换为panic vm.panic_on_oom = 1 # 表示强制Linux VM最低保留多少空闲内存(Kbytes) vm.min_free_kbytes = 1048576 # 该值高于100,则将导致内核倾向于回收directory和inode cache vm.vfs_cache_pressure = 250 # 表示系统进行交换行为的程度,数值(0-100)越高,越可能发生磁盘交换 vm.swappiness = 20 # 仅用10%做为系统cache vm.dirty_ratio = 10 # 增加系统文件描述符限制 2^20-1 fs.file-max = 1048575 # 网络层优化 # listen()的默认参数,挂起请求的最大数量,默认128 net.core.somaxconn = 1024 # 增加Linux自动调整TCP缓冲区限制 net.core.wmem_default = 8388608 net.core.rmem_default = 8388608 net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 # 进入包的最大设备队列.默认是300 net.core.netdev_max_backlog = 2000 # 开启SYN洪水攻击保护 net.ipv4.tcp_syncookies = 1 # 开启并记录欺骗,源路由和重定向包 net.ipv4.conf.all.log_martians = 1 net.ipv4.conf.default.log_martians = 1 # 处理无源路由的包 net.ipv4.conf.all.accept_source_route = 0 net.ipv4.conf.default.accept_source_route = 0 # 开启反向路径过滤 net.ipv4.conf.all.rp_filter = 1 net.ipv4.conf.default.rp_filter = 1 # 确保无人能修改路由表 net.ipv4.conf.all.accept_redirects = 0 net.ipv4.conf.default.accept_redirects = 0 net.ipv4.conf.all.secure_redirects = 0 net.ipv4.conf.default.secure_redirects = 0 # 增加系统IP端口限制 net.ipv4.ip_local_port_range = 9000 65533 # TTL net.ipv4.ip_default_ttl = 64 # 增加TCP最大缓冲区大小 net.ipv4.tcp_rmem = 4096 87380 8388608 net.ipv4.tcp_wmem = 4096 32768 8388608 # Tcp自动窗口 net.ipv4.tcp_window_scaling = 1 # 进入SYN包的最大请求队列.默认1024 net.ipv4.tcp_max_syn_backlog = 8192 # 打开TIME-WAIT套接字重用功能,对于存在大量连接的Web服务器非常有效。 net.ipv4.tcp_tw_recycle = 1 net.ipv4.tcp_tw_reuse = 0 # 表示是否启用以一种比超时重发更精确的方法(请参阅 RFC 1323)来启用对 RTT 的计算;为了实现更好的性能应该启用这个选项 net.ipv4.tcp_timestamps = 0 # 表示本机向外发起TCP SYN连接超时重传的次数 net.ipv4.tcp_syn_retries = 2 net.ipv4.tcp_synack_retries = 2 # 减少处于FIN-WAIT-2连接状态的时间,使系统可以处理更多的连接。 net.ipv4.tcp_fin_timeout = 10 # 减少TCP KeepAlive连接侦测的时间,使系统可以处理更多的连接。 # 如果某个TCP连接在idle 300秒后,内核才发起probe.如果probe 2次(每次2秒)不成功,内核才彻底放弃,认为该连接已失效. net.ipv4.tcp_keepalive_time = 300 net.ipv4.tcp_keepalive_probes = 2 net.ipv4.tcp_keepalive_intvl = 2 # 系统所能处理不属于任何进程的TCP sockets最大数量 net.ipv4.tcp_max_orphans = 262144 # 系统同时保持TIME_WAIT套接字的最大数量,如果超过这个数字,TIME_WAIT套接字将立刻被清除并打印警告信息。 net.ipv4.tcp_max_tw_buckets = 20000 # arp_table的缓存限制优化 net.ipv4.neigh.default.gc_thresh1 = 128 net.ipv4.neigh.default.gc_thresh2 = 512 net.ipv4.neigh.default.gc_thresh3 = 4096 EOF