Installation guide

Chapter 24. Upgrading Your Current System
This chapter explains the various methods available for upgrading your Red Hat Enterprise Linux
system.
24 .1. Det ermining Whet her t o Upgrade or Re-Inst all
Red Hat does not support upgrades from earlier major versions
Although an aco nd a provides an option for upgrading from earlier major versions of Red Hat
Enterprise Linux to Red Hat Enterprise Linux 5.11, Red Hat does not currently support this.
More generally, Red Hat does not support in-place upgrades between any major versions of
Red Hat Enterprise Linux. (A major version is denoted by a whole number version change. For
example, Red Hat Enterprise Linux 4 and Red Hat Enterprise Linux 5 are both major versions
of Red Hat Enterprise Linux.)
In-place upgrades across major releases do not preserve all system settings, services or
custom configurations. Consequently, Red Hat strongly recommends fresh installations when
upgrading from one major version to another.
While upgrading from Red Hat Enterprise Linux version 4 Update 4 is technically possible, you are
more likely to have a consistent experience by backing up your data and then installing this release
of Red Hat Enterprise Linux 5.11 over your previous Red Hat Enterprise Linux installation.
To upgrade from Red Hat Enterprise Linux 4 you should bring your system up to date using RHN
before performing the upgrade.
This recommended reinstallation method helps to ensure the best system stability possible.
For more information about re-installing your Red Hat Enterprise Linux system, refer to the
Whitepapers available online at http://www.redhat.com/rhel/resource_center/.
If you currently use Red Hat Enterprise Linux 4 Update 4, you can perform a traditional, installation
program-based upgrade.
However, before you choose to upgrade your system, there are a few things you should keep in mind:
Individual package configuration files may or may not work after performing an upgrade due to
changes in various configuration file formats or layouts.
Third party or ISV applications may not work correctly following the upgrade.
If you have one of Red Hat's layered products (such as the Cluster Suite) installed, it may need to
be manually upgraded after the Red Hat Enterprise Linux upgrade has been completed.
If you have package repositories from providers other than Red Hat enabled, note that software
installed from those repositories may not function properly after a system upgrade. Red Hat
cannot guarantee that such repositories are up-to-date.
Upgrading your system installs updated versions of the packages which are currently installed on
your system.
⁠Chapt er 2 4 . Upgrading Your Current Syst em
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