有时候CentOS默认的yum源不一定是国内镜像，导致yum在线安装及更新速度不是很理想。这时候需要将yum源设置为国内镜像站点。国内主要开源的开源镜像站点应该是网易和阿里云了。

1、修改CentOS默认yum源为mirrors.163.com

• 1、首先备份系统自带yum源配置文件/etc/yum.repos.d/CentOS-Base.repo

[wujiahao@47.98.32.222 ~]# mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

• 2、进入yum源配置文件所在的文件夹

[wujiahao@47.98.32.222 ~]]# cd /etc/yum.repos.d/

• 3、下载163的yum源配置文件到上面那个文件夹内

CentOS7

[wujiahao@47.98.32.222 yum.repos.d]# wget http://mirrors.163.com/.help/CentOS7-Base-163.repo

CentOS6

[wujiahao@47.98.32.222 yum.repos.d]# wget http://mirrors.163.com/.help/CentOS6-Base-163.repo

CentOS5

[wujiahao@47.98.32.222 yum.repos.d]# wget http://mirrors.163.com/.help/CentOS5-Base-163.repo

• 4、运行yum makecache生成缓存

[wujiahao@47.98.32.222 yum.repos.d]# yum makecache

• 5、这时候再更新系统就会看到以下mirrors.163.com信息

[wujiahao@47.98.32.222 yum.repos.d]# yum -y update

已加载插件：fastestmirror, refresh-packagekit, security
设置更新进程Loading mirror speeds from cached hostfile
* base: mirrors.163.com
* extras: mirrors.163.com
* updates: mirrors.163.com

2、修改CentOS默认yum源为mirrors.aliyun.com

• 1、首先备份系统自带yum源配置文件/etc/yum.repos.d/CentOS-Base.repo

[wujiahao@47.98.32.222 ~]# mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

• 2、下载ailiyun的yum源配置文件到/etc/yum.repos.d/

CentOS7

[wujiahao@47.98.32.222 ~]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

CentOS6

[wujiahao@47.98.32.222 ~]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo

CentOS5

[wujiahao@47.98.32.222 ~]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo

• 3、运行yum makecache生成缓存

[wujiahao@47.98.32.222 ~]# yum makecache

• 4、这时候再更新系统就会看到以下mirrors.aliyun.com信息

[wujiahao@47.98.32.222 ~]# yum -y update

已加载插件：fastestmirror, refresh-packagekit, security
设置更新进程Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
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