一、内核内存配置检查：

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可以通过以下办法来查看启动时内核是否支持64G内存

首先要弄清启动时用的是哪个内核

[root@study ~]# cat /boot/grub/grub.conf

...

default=0 （说明第一个条目是默认的启动）

timeout=5

splashimage=(hd0,0)/grub/splash.xpm.gz

hiddenmenu

root (hd0,0)

kernel /vmlinuz-2.6.9-34.ELsmp ro root=/dev/VolGroup00/LogVol00 rhgb quiet

initrd /initrd-2.6.9-34.ELsmp.img

title Red Hat Enterprise Linux AS-up (2.6.9-34.EL)

root (hd0,0)

kernel /vmlinuz-2.6.9-34.EL ro root=/dev/VolGroup00/LogVol00 rhgb quiet

initrd /initrd-2.6.9-34.EL.img

我的内核是vmlinuz-2.6.9-34.ELsmp

对应安装时的内核编译文件就是

/boot/config-2.6.9-34.ELsmp

检查高内存支持

[root@study ~]# more /boot/config-2.6.9-34.ELsmp |grep 4G

# CONFIG_X86_4G is not set

# CONFIG_X86_4G_VM_LAYOUT is not set

# CONFIG_HIGHMEM4G is not set

CONFIG_HIGHMEM64G=y 说明我的内核编译时选择了64G内存支持，

只有4G支持的情况会类似：

[root@study ~]# more /boot/config-2.6.9-34.EL |grep 4G

# CONFIG_X86_4G is not set

# CONFIG_X86_4G_VM_LAYOUT is not set

CONFIG_HIGHMEM4G=y

# CONFIG_HIGHMEM64G is not set