Installation guide

Appendix A.

Upgrading Your Current System

This appendix explains the various methods available for upgrading your Red Hat Enterprise Linux

system.

A.1. Determining Whether to Upgrade or Re-Install

Although upgrades are supported from Red Hat Enterprise Linux versions 2.1 and 3 by the Red Hat

Enterprise Linux family on x86 processors (or Red Hat Enterprise Linux 3 on an AMD64, EM64T

or Itanimum system), you are more likely to have a consistent experience by backing up your data

and then installing this release of Red Hat Enterprise Linux 4 over your previous Red Hat Enterprise

Linux installation.

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 Technical

Whitepapers available online at http://www.redhat.com/docs/wp/.

If you currently use Red Hat Enterprise Linux version 2.1 or 3 on an x86 system (or Red Hat Enterprise

Linux 3 on an AMD64, EM64T or Itanimum system), you can perform a traditional, installation

program-based upgrade.

However, before you chose 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.

• 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.

• Third party or ISV applications may not work correctly following the upgrade.

Upgrading your system installs the modular 2.6.x kernel as well as updated versions of the packages

which are currently installed on your system.

The upgrade process preserves existing conﬁguration ﬁles by renaming them with an .rpmsave ex-

tension (for example, sendmail.cf.rpmsave). The upgrade process also creates a log of its actions

in /root/upgrade.log.

Caution

As software evolves, conﬁguration ﬁle formats can change. It is very important to carefully compare

your original conﬁguration ﬁles to the new ﬁles before integrating your changes.

Note

It is always a good idea to back up any data that you have on your systems. For example, if you are

upgrading or creating a dual-boot system, you should back up any data you wish to keep on your

hard drive(s). Mistakes do happen and can result in the loss of all of your data.