When a CentOS 5.6 machine needs to upgrade the memory to 6 GB, the system is found to be 32-bit, so the search can enable the 32-bit system to support 4 GB memory or above.
How does one enable 32-bit linux/Centos to support 8 GB memory? The kernel-based PAE installation supports a method larger than 4 GB memory. Linux/Centos 32bit OS does not support 4 GB memory or above by default. you can install a kernel-PAE patch to solve this problem. It is best to back up a snapshot of the virtual machine before the operation, in case of an accident, it can be restored to normal.
The following are the steps:
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[root@www.ctohome.com]
# free
total used
free
shared buffers cached
Mem: 3881968 637928 3244040 0 111292 461680
-/+ buffers
/cache
: 64956 3817012
Swap: 4192924 0 4192924
[root@www.ctohome.com]
# yum install kernel-PAE
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
centos-burstnet | 1.1 kB 00:00
updates-burstnet | 1.9 kB 00:00
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package kernel-PAE.i686 0:2.6.18-194.32.1.el5
set
to be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================================================================================================================
Package Arch Version Repository Size
================================================================================================================================================================================
Installing:
kernel-PAE i686 2.6.18-194.32.1.el5 updates-burstnet 17 M
Transaction Summary
================================================================================================================================================================================
Install 1 Package(s)
Upgrade 0 Package(s)
Total download size: 17 M
Is this ok [y
/N
]: y
Downloading Packages:
kernel-PAE-2.6.18-194.32.1.el5.i686.rpm | 17 MB 00:01
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : kernel-PAE 1
/1
Installed:
kernel-PAE.i686 0:2.6.18-194.32.1.el5
Complete!
[root@www.ctohome.com]
# free
total used
free
shared buffers cached
Mem: 3881968 637928 3244040 0 111292 461680
-/+ buffers
/cache
: 64956 3817012
Swap: 4192924 0 4192924
[root@www.ctohome.com]
# vi /boot/grub/grub.conf
default=0
# (Change default = 1 to default = 0)
timeout=5
splashimage=(hd0,0)
/grub/splash
.xpm.gz
hiddenmenu
title CentOS (2.6.18-194.32.1.el5PAE)
# (If this line of PAE exists, the pae kernel is successfully installed)
root (hd0,0)
kernel
/vmlinuz-2
.6.18-194.32.1.el5PAE ro root=LABEL=/
initrd
/initrd-2
.6.18-194.32.1.el5PAE.img
title CentOS (2.6.18-194.32.1.el5)
root (hd0,0)
kernel
/vmlinuz-2
.6.18-194.32.1.el5 ro root=LABEL=/
initrd
/initrd-2
.6.18-194.32.1.el5.img
title CentOS (2.6.18-194.el5)
root (hd0,0)
kernel
/vmlinuz-2
.6.18-194.el5 ro root=LABEL=/
initrd
/initrd-2
.6.18-194.el5.img
[root@www.ctohome.com]
# Reboot (restart the server here and pray that sometimes the motherboard or Nic is not supported, you can only contact the IDC)
Broadcast message from root (pts
/0
) (Thu May 19 18:52:34 2011):
The system is going down
for
reboot NOW!
[root@www.ctohome.com]
# free
total used
free
shared buffers cached
Mem: 8295488 215248 8080240 0 19460 142592
-/+ buffers
/cache
: 53196 8242292
Swap: 4192924 0 4192924
The upgrade is complete and supports large memory.