Use memory larger than 4 GB in Fedora9

Recently I got a few new IBM servers for testing. The server configuration is very good, with a nominal 8 GB memory, after Fedora9 is installed, run the "free" command to check the machine memory. However, the system shows that the memory size is only 3 GB, and it is not as standard as to 8 GB: totalusedfreesharedbufferscachedMem: 3106944213288289365609060143584-/+ buffers/cache: 6064430

Recently I got a few new IBM servers for testing. The server configuration is very good, with a nominal 8 GB memory, after ora 9 is installed, run the "free" command to check the machine memory. However, the system shows that the memory size is only 3 GB, and it is not as standard as 8 GB:

Total used free shared buffers cached
Mem: 3106944 213288 2893656 0 9060 143584
-/+ Buffers/cache: 60644 3046300
Swap: 0 0 0

At first, I thought this machine had less memory. wangyuneu asked me to go to the BIOS to check the memory size. I found in the BIOS that the machine memory is indeed 8 GB, another colleague also reminded me if it was because the operating system does not support it. The Windows 2003 installed by him also has a similar problem and only recognizes 4 GB memory. So we can basically determine that this problem should be related to the system.

Originally, I was going to re-compile the Fedora 9 kernel to support 4 GB of memory. When looking for the kernel source code, I accidentally found that the yum library of Fedora 9 contains a kernel-PAE package, in this way, you do not have to re-compile the Fedora 9 kernel as much as possible. You only need to execute the following command:

Yum install kernel-PAE
Yum remove kernel

After the execution is complete, restart the server and use "free" to view the memory size:

Total used free shared buffers cached
Mem: 8308848 142780 8166068 0 5960 74948
-/+ Buffers/cache: 61872 8246976
Swap: 0 0 0

In this way, the memory reaches 8 GB and the problem is solved.