原文 http://itindex.net/detail/51140-centos7-web-服务器
1、加大打开文件数的限制（open files）
查看
ulimit -n
ulimit -a
vi /etc/security/limits.conf
最后添加
* soft nofile 1024000
* hard nofile 1024000
hadoop - nofile 1024000
hadoop - nproc 1024000
用户进程限制
vi /etc/security/limits.d/20-nproc.conf
#加大普通用户限制 也可以改为unlimited
* soft nproc 40960
root soft nproc unlimited
此步骤需要重启机器生效，可以设置完后再重启
2、网络线程优化
vi /etc/sysctl.conf
加入下面几行
# Disable IPv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
# Determines how often to check for stale neighbor entries.
net.ipv4.neigh.default.gc_stale_time=120
# Using arp_announce/arp_ignore to solve the ARP Problem
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.all.arp_announce=2
vm.swappiness = 0
net.ipv4.tcp_max_tw_buckets = 5000
net.ipv4.tcp_max_syn_backlog = 1024
net.ipv4.tcp_synack_retries = 2
net.ipv4.conf.lo.arp_announce=2
net.ipv4.tcp_keepalive_time = 1800
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_intvl = 15
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_fin_timeout = 30
执行下面命令生效
/sbin/sysctl -p