使32位CentOS5支持4G内存

转自：http://hi.baidu.com/hfr6666/blog/item/72e0e02202c218ac4723e8e3.html

主要需要2个方面设置

1.bios:在bios里开启对大内存的设置

2.安装支持大内存的kernel

centos 5.0 默认安装 for i386的内核不支持 4g+的内存
需要安装上kernel-hugemem

yum install kernel-hugemem
结果发现 centos 下面 没有 kernel-hugemem这个rpm包了

已经改名为kernel-PAE
尝试用yum安装
yum install kernel-PAE
后来查看安装光盘，发现亦可用以下命令直接安装（注意，我的安装光盘已复制到/home目录下）：

rpm -ivh /home/CentOS/kernel-PAE-2.6.18-8.el5.i686.rpm

安装好后
more /boot/grub/grub.conf
如果看到如下代码 代表PAE内核已经安装好了
# cat /etc/grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/md2
#          initrd /initrd-version.img
#boot=/dev/md0
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.18-92.1.18.el5PAE)
root (hd0,0)
kernel /vmlinuz-2.6.18-92.1.18.el5PAE ro root=/dev/md2
initrd /initrd-2.6.18-92.1.18.el5PAE.img
title CentOS (2.6.18-8.el5)
root (hd0,0)
kernel /vmlinuz-2.6.18-8.el5 ro root=/dev/md2
initrd /initrd-2.6.18-8.el5.img

修改设置为默认启动

default=0

init 6,重启服务器
再执行top/free内存已经是4.1g了

# free
total       used       free     shared    buffers     cached
Mem:       4138228     440908    3697320          0      49716     262556

#top

top - 17:19:32 up 2:43, 3 users, load average: 0.04, 0.02, 0.00
Tasks: 98 total,   1 running, 97 sleeping,   0 stopped,   0 zombie
Cpu(s): 0.0%us, 0.2%sy, 0.0%ni, 99.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem:   4138228k total,   440784k used, 3697444k free,    49732k buffers
Swap: 8385784k total,        0k used, 8385784k free,   262556k cached