linux内核参数优化

linux内核参数优化

主要针对/etc/sysctl.conf文件
 
/etc/sysctl.conf是一个允许你改变正在运行中的Linux系统的接口。
它包含一些TCP/IP堆栈和虚拟内存系统的高级选项，可用来控制Linux网络配置，由于/proc/sys/net目录内容的临时性，
建议把TCPIP参数的修改添加到/etc/sysctl.conf文件, 然后保存文件，使用命令“/sbin/sysctl –p”使之立即生效。具体修改方案参照上文：

参考配置一：
net.core.rmem_default = 256960
net.core.rmem_max = 513920
net.core.wmem_default = 256960
net.core.wmem_max = 513920
net.core.netdev_max_backlog = 2000
net.core.somaxconn = 2048
net.core.optmem_max = 81920
net.ipv4.tcp_mem = 131072  262144  524288
net.ipv4.tcp_rmem = 8760  256960  4088000
net.ipv4.tcp_wmem = 8760  256960  4088000
net.ipv4.tcp_keepalive_time = 1800
net.ipv4.tcp_keepalive_intvl = 30
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_sack = 1
net.ipv4.tcp_fack = 1
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_fin_timeout = 30
net.ipv4.ip_local_port_range = 1024  65000
net.ipv4.tcp_max_syn_backlog = 2048

参考配置二：
#原有字段
net.ipv4.tcp_syncookies = 1
#新增字段
fs.file-max = 999999
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_keepalive_time = 600
net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_max_tw_buckets = 5000
net.ipv4.ip_local_port_range = 1024 61000
net.ipv4.tcp_rmem = 10240 87380 12582912
net.ipv4.tcp_wmem = 10240 87380 12582912
net.core.netdev_max_backlog = 8096
net.core.rmem_default = 6291456
net.core.wmem_default = 6291456
net.core.rmem_max = 12582912
net.core.wmem_max = 12582912
net.ipv4.tcp_max_syn_backlog = 1024

参考配置三：
net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_keepalive_time = 1200
net.ipv4.tcp_syncookies = 0
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.ip_local_port_range = 1024    65000
net.ipv4.tcp_max_syn_backlog = 8192
net.ipv4.tcp_max_tw_buckets = 5000
fs.file-max = 655360

最终增加使用的配置：
net.core.somaxconn = 2048
net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_keepalive_time = 1200
net.ipv4.tcp_tw_reuse = 1
net.core.netdev_max_backlog = 8096
net.ipv4.tcp_max_syn_backlog = 8192

总结：

不要盲目的追求所谓的linux内核优化，设置内核参数时，一定要知道这个参数有什么作用，不要盲目的在网上找个模板就设置了，

如果不知道它的作用就不要设置，不要为了优化而优化，线上环境切记不能随意设置。

参考：
http://pengyao.org/sysctl-1.html
http://www.jianshu.com/p/9a8e383b5b49
http://blog.youkuaiyun.com/gao715108023/article/details/27171371
http://www.linuxde.net/2013/07/14796.html
http://blog.youkuaiyun.com/21aspnet/article/details/6584792