关于CentOS update比较慢的解决办法

      centOS是RHEL的源代码再次编译出的社区操作系统，所以兼顾RHEL的所有优秀特点，而且完全免费，许多考虑成本的公司都用centOS部署服务器。 但是此操作系统自带的官方更新下载速度太慢，经过网上查阅资料，按照如下步骤可以解决。

1.进入/etc/yum.repos.d/的目录  命令：cd /etc/yum.repos.d/

2.删除两个文件CentOS-Base.repo 和CentOS-Base.repo.bak    命令：mv CentOS-Base.repo CentOS-Base.repo.bak

3.在此目录下重新建立文件 CentOS-Base.repo   命令：vi CentOS-Base.repo

4.在 CentOS-Base.repo 文件中加入以下内容：

# 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/$basearch/   
gpgcheck=1   
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5   
#released updates   
[updates]   
name=CentOS-$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   
#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/$basearch/   
gpgcheck=1   
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5   
#additional packages that may be useful   
[extras]   
name=CentOS-$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   
#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

   5.导入 key

     # rpm –import http://ftp.sjtu.edu.cn/centos/5/os/i386/RPM-GPG-KEY-CentOS-5

   6.运行，测试

     # yum update  

   7.全部删除临时文件

      #yum clean all