通用linux接口服务器参数调优

1. 如果需要支撑百万级同时在线数，需要对linux默认内核参数进行调整，我们的典型配置是在
/etc/sysctl.conf增加以下内容：

net.ipv4.tcp_max_orphans = 262144
net.ipv4.tcp_no_metrics_save=1
net.ipv4.tcp_window_scaling = 0
net.ipv4.tcp_max_syn_backlog = 120000
    net.core.netdev_max_backlog = 120000
    net.core.somaxconn = 12000
    net.ipv4.tcp_fin_timeout = 10
    net.ipv4.tcp_tw_reuse = 1
    net.ipv4.tcp_tw_recycle = 1
    net.ipv4.tcp_max_tw_buckets = 1000
    net.ipv4.tcp_abort_on_overflow = 1
    net.ipv4.tcp_sack = 0
    net.ipv4.tcp_rmem = 4096 8192 32768
    net.ipv4.tcp_wmem = 4096 8192 32768
    net.ipv4.tcp_timestamps = 0
    net.ipv4.tcp_mem = 3075840  4101120  12303360
    net.ipv4.tcp_keepalive_time = 30
    net.ipv4.tcp_keepalive_probes = 5
    net.ipv4.tcp_keepalive_intvl = 15
    net.ipv4.tcp_synack_retries = 2
    net.ipv4.tcp_syn_retries = 2
net.core.rmem_max=16777216
net.core.wmem_max=16777216
    net.ipv4.ip_local_port_range = 1024     65535
net.ipv4.tcp_syncookies = 0

修改/etc/security/limits.conf配置:
*               soft    nofile          1200000
*               hard    nofile          1200000

root hard nofile 1000000
root soft nofile 1000000
root soft core unlimited
root soft stack 10240
ubuntu hard nofile 1000000
ubuntu soft nofile 1000000
ubuntu soft core unlimited
ubuntu soft stack 10240

*  hard nofile 1000000
*  soft nofile 1000000