Enable 32-bit Centos to support memory larger than 4 GB

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:

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768 [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.