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1.导入密钥
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
2.添加库
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm
3.更新内核
yum --enablerepo=elrepo-kernel install kernel-ml
4.查询所有内核列表
rpm -qa | grep kernel
5.查看启动内核
awk -F\' '$1=="menuentry " {print $2}' /etc/grub2.cfg
6.修改默认启动内核
grub2-set-default 0
7.重启
reboot
8.查询默认内核是否为:4.9.8-1.el7.elrepo.x86_64
uname -r
9.修改配置开启BBR
echo "net.core.default_qdisc=fq" >> /etc/sysctl.conf && echo "net.ipv4.tcp_congestion_control=bbr" >> /etc/sysctl.conf
10.加载新配置,查看内核是否已开启BBR
sysctl -p && sysctl net.ipv4.tcp_available_congestion_control
11.查看BBR是否启动,返回值有 tcp_bbr 模块即说明已启动
lsmod | grep bbr
12.如果需要关闭BBR,用vi编辑 /etc/sysctl.conf,删除其中的两行:
net.core.default_qdisc = fq
net.ipv4.tcp_congestion_control = bbr
13.然后执行命令:
sysctl -p