yum使用http://mirror.centos.org/的镜像升级和下载软件有点小慢，现在网易干了件好事就是有了http://mirrors.163.com/这个开源镜像站，速度还不是一般的快。

根据网上的文章“使用163开源镜像升级你的CentOS”修改，很简单的，操作过程如下，做个笔记。平时用的是CentOS 4.7 sever版，网上多是CentOS 5.X版的，只是改动了gpgkey的验证版本和网站，因为baseurl的链接都是163的。当然不修改也可以，但是163镜像如果没有及时和CentOS镜像同步，估计使用yum时会有问题只是估计。

1.备份系统原来的CentOS-Base.repo文件：

cd /etc/yum.repos.d/

#cp -a CentOS-Base.repo CentOS-Base.repo.bak

2.用vi打开CentOS-Base.repo文件：

#vim CentOS-Base.repo

修改后的CentOS-Base.repo文件,代码如下：

# CentOS-Base.repo

#

# This file uses a new mirrorlist system developed by Lance Davis for CentOS.

# The mirror system uses the connecting IP address of the client and the

# update status of each mirror to pick mirrors that are updated to and

# geographically close to the client. You should use this for CentOS updates

# unless you are manually picking other mirrors.

#

# If the mirrorlist= does not work for you, as a fall back you can try the

# remarked out baseurl= line instead.

#

#

[base]

name=CentOS-$releasever - Base

#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os

#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/

baseurl=http://mirrors.163.com/centos/$releasever/os/$basearch/

gpgcheck=1

#gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5

gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-4

#released updates

[updates]

name=CentOS-$releasever - Updates

#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates

#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/

baseurl=http://mirrors.163.com/centos/$releasever/updates/$basearch/

gpgcheck=1

#gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5

gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-4

#packages used/produced in the build but not released

[addons]

name=CentOS-$releasever - Addons

#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=addons

#baseurl=http://mirror.centos.org/centos/$releasever/addons/$basearch/

baseurl=http://mirrors.163.com/centos/$releasever/addons/$basearch/

gpgcheck=1

#gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5

gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-4

#additional packages that may be useful

[extras]

name=CentOS-$releasever - Extras

#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras

#baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/

baseurl=http://mirrors.163.com/centos/$releasever/extras/$basearch/

gpgcheck=1

#gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5

gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-4

#additional packages that extend functionality of existing packages

[centosplus]

name=CentOS-$releasever - Plus

#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus

#baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/

baseurl=http://mirrors.163.com/centos/$releasever/centosplus/$basearch/

gpgcheck=1

enabled=0

#gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5

gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-4