yum改成网易的源

用网易的源会快很多，步骤如下：

1、首先备份/etc/yum.repos.d/CentOS-Base.repo

1. mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

2、根据CentOS版本选择操作
CentOS-5

1. wget http://mirrors.163.com/.help/CentOS5-Base-163.repo -O /etc/yum.repos.d/CentOS-Base.repo
2. yum makecache

CentOS-6

1. wget http://mirrors.163.com/.help/CentOS6-Base-163.repo  -O /etc/yum.repos.d/CentOS-Base.repo
2. yum makecache

文章来源:《http://www.centos.bz/2011/11/centos-163-yum-repo/》