Centos 7 安装新内核启用BBR

1：首先yum update -y更新到最新CentOS 7.3 1611

cat /etc/redhat-release
CentOS Linux release 7.3.1611 (Core)

2: 安装elrepo内核

rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
rpm -Uvh https://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm

然后先rpm -qa |grep kernel

先卸载旧的kernel-headers，kernel-tools, kernel-tools-libs，只保留内核，然后

yum --enablerepo=elrepo-kernel install kernel-ml

就会安装elrepo正式版4.9内核，跟着再安装

yum --enablerepo=elrepo-kernel install kernel-ml-headers kernel-ml-tools kernel-ml-tools-libs kernel-ml-devel

然后

awk -F\' '$1=="menuentry " {print $2}' /etc/grub2.cfg

看看内核启动顺序，然后

grub2-set-default 0

把kernel-ml 4.9设为默认，重启

3：跟着

vim /etc/sysctl.conf

加两行：

net.core.default_qdisc = fq
net.ipv4.tcp_congestion_control = bbr

sysctl -p

生效，最后，重启，验证

sysctl -a|grep tcp_congestion_control

结果：

net.ipv4.tcp_congestion_control = bbr