Red Hat Knowledgebase

The recommended "upgrade" path to Red Hat Enterprise Linux is a misnomer. We recommend that you back up any important data, perform a clean installation with the newer version, then restore your existing data.

To be technically accurate, there is an upgrade option to allow an upgrade without requiring a full reinstall. To get this functionality, insert the installation CD of the new version and enter either of these commands on the boot prompt:

linux upgrade

linux upgradeany

This will walk you through the upgrade procedure, which very closely resembles a normal installation.

Warning: The upgrade option is supported by Red Hat Technical Support but is known to cause erratic system behavior in some cases.

Note: The upgrade button will only appear when the commands above are used.

Important: Red Hat recommends that you do a complete back-up of your system before you attempt the upgrade. The preferred method of upgrading is to back-up your system, perform a clean install of Red Hat Enterprise Linux version 4, and migrate your data. Red Hat has only tested installation without any modifications to configuration files and the tested systems were absent of any third party (non-Red Hat) applications.

Kindly refer to the Red Hat Enterprise Linux 3 installation guide at http://www.redhat.com/docs/manuals/enterprise/RHEL-3-Manual/x8664-multi-install-guide/ap-upgrade.html for more details.