RedHat 5.7升级为PAE内核，并更新yum源

内核升级为PAE的方式

1.安装好RedHat 5.7的系统后，将rhel-server-5.7-i386-dvd.iso解压，进入下列目录下，下面两个包传到redhat 5.7里。

2.执行安装命令：

yum install -y kernel-PAE-* --nogpgcheck

3.安装好后进入/boot/grub/grub.conf目录

[root@redhat-57 ~]# vi /boot/grub/grub.conf

将default=1改为default=0并保存
4.然后reboot重启，内核即成功改为2.6.18-274.el5PAE。

更新yum源

1.将redhat的yum源替换成centos的源

[root@redhat-57 ~]# cd /etc/yum.repos.d/
[root@redhat-57 yum.repos.d]# ll
total 24
-rw-r--r-- 1 root root   67 Apr 28 17:53 redhat.repo
-rw-r--r-- 1 root root  561 Jun 29  2011 rhel-debuginfo.repo
-rw-r--r-- 1 root root 1749 Apr 28 17:52 rhel-source.repo

2.如果没有rhel-source.repo文件，则需要新建，在rhel-source.repo中填入一下内容：

[root@redhat-57 yum.repos.d]# vi rhel-source.repo

# CentOS-Base.repo
#
# 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-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/5.10/os/i386/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-5#released updates
[updates]
name=CentOS-$releasever - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/5.10/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-5#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/5.10/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-5#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/5.10/centosplus/$basearch/
gpgcheck=1
enabled=0    
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-5#contrib - packages by Centos Users 
[contrib]
name=CentOS-$releasever - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/5.10/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-5

清理缓存

[root@redhat-57 yum.repos.d]# yum clean all

更新缓存

[root@redhat-57 yum.repos.d]# yum makecache