在CentOS系統中，yum是個好東西，一組件可以直接通過yum來安裝，但系統默認的yum源速度往往不盡人意，為了達到快遞安裝的目的，在這裡就需要修改yum源
中科大的Centos 開源鏡像站點. http://centos.ustc.edu.cn/
執行以下命令就可以了
cd /etc/yum.repos.d
mv CentOS-Base.repo CentOS-Base.repo.bak
wget http://centos.ustc.edu.cn/CentOS-Base.repo.5
mv CentOS-Base.repo.5 CentOS-Base.repo
cat CentOS-Base.repo
[base]
name=CentOS-$releasever - Base
baseurl=http://centos.ustc.edu.cn/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
#released updates
[updates]
name=CentOS-$releasever - Updates
baseurl=http://centos.ustc.edu.cn/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
#packages used/produced in the build but not released
[addons]
name=CentOS-$releasever - Addons
baseurl=http://centos.ustc.edu.cn/centos/$releasever/addons/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
baseurl=http://centos.ustc.edu.cn/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
baseurl=http://centos.ustc.edu.cn/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://centos.ustc.edu.cn/centos/RPM-GPG-KEY-CentOS-5
也可以使用， http://mirrors.163.com/ http://mirrors.sohu.com
