Overview Of Kernel Packages - Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual

Chapter 40.
Manually Upgrading the Kernel
The Red Hat Enterprise Linux kernel is custom built by the Red Hat Enterprise Linux kernel team to
ensure its integrity and compatibility with supported hardware. Before Red Hat releases a kernel, it
must first pass a rigorous set of quality assurance tests.
Red Hat Enterprise Linux kernels are packaged in RPM format so that they are easy to upgrade and
verify using the Package Management Tool, or the yum command. The Package Management Tool
automatically queries the Red Hat Enterprise Linux servers and determines which packages need to
be updated on your machine, including the kernel. This chapter is only useful for those individuals that
require manual updating of kernel packages, without using the yum command.
Warning
Building a custom kernel is not supported by the Red Hat Global Services Support team,
and therefore is not explored in this manual.
Tip
The use of yum is highly recommended by Red Hat for installing upgraded kernels.
For more information on Red Hat Network, the Package Management Tool, and yum, refer to
Chapter 13, Red Hat Network.

40.1. Overview of Kernel Packages

Red Hat Enterprise Linux contains the following kernel packages (some may not apply to your
architecture):
• kernel — Contains the kernel for multi-processor systems. For x86 system, only the first 4GB of
RAM is used. As such, x86 systems with over 4GB of RAM should use the kernel-PAE.
• kernel-devel — Contains the kernel headers and makefiles sufficient to build modules against
the kernel package.
• kernel-PAE (only for i686 systems) — This package offers the following key configuration option
(in addition to the options already enabled for the kernel package):
• PAE (Physical Address Extension) support for systems with more than 4GB of RAM, and reliably
up to 16GB.
Important
Physical Address Extension allows x86 processors to address up to 64GB of physical
RAM, but due to differences between the Red Hat Enterprise Linux 4 and 5 kernels,
only Red Hat Enterprise Linux 4 (with the kernel-hugemem package) is able to
reliably address all 64GB of memory. Additionally, the Red Hat Enterprise Linux 5
PAE variant does not allow 4GB of addressable memory per-process like the Red
Hat Enterprise Linux 4 kernel-hugemem variant does. However, the x86_64 kernel
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