Linux内核优化

优化Linux内核参数

vi /etc/sysctl.conf

在末尾增加以下内容：

# Add
net.ipv4.tcp_max_syn_backlog = 65536
net.core.netdev_max_backlog =  32768
net.core.somaxconn = 32768
 
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
 
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_synack_retries = 2
net.ipv4.tcp_syn_retries = 2
 
#net.ipv4.tcp_tw_recycle = 1
#net.ipv4.tcp_tw_len = 1
net.ipv4.tcp_tw_reuse = 1
 
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_max_orphans = 3276800
 
#net.ipv4.tcp_fin_timeout = 30
#net.ipv4.tcp_keepalive_time = 120
net.ipv4.ip_local_port_range = 1024  65535
fs.file-max = 65536
net.ipv4.ip_forward=1

使配置立即生效：

/sbin/sysctl -p

六、增大open files的限制值

vi /etc/security/limits.conf

在“# End of file”上面添加如下：

*  -  nofile  65536

该语句表示：每一个用户的默认打开文件数是65536。
修改完毕之后，重启服务器。然后输入：

ulimit -a

输出结果如下：

core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
file size               (blocks, -f) unlimited
pending signals                 (-i) 1024
max locked memory       (kbytes, -l) 32
max memory size         (kbytes, -m) unlimited
open files                      (-n) 65536
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 16384
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

只要open files的限制值达到65536，则问题解决。