If you have an older installation of Red Hat Linux on your system (Red Hat Linux 6.2 or higher), you may want to upgrade to Red Hat Linux 8.0 rather than installing from scratch so that you can save any files that are currently on your system. This chapter walks you through a typical Red Hat Linux 8.0 upgrade. (You should review the beginning of Chapter 2, up through the point where you choose the Upgrade installation, before reading this chapter.)
You must have Red Hat Linux 6.2 or later installed on your machine to perform an upgrade.
Red Hat Linux 8.0 allows you to upgrade from prior versions of Red Hat Linux — but only if you have version 6.2 and later installed. Upgrading your system installs the modular 2.4.x kernel as well as updated versions of the packages that are currently installed on your system. If you choose to upgrade, keep in mind that the Upgrade installation can take a great deal longer than the regular installation because the Upgrade installation has to perform a lot more disk access to ensure the continued integrity of the existing data.
The upgrade process preserves existing configuration files by renaming them with an .rpmsave extension (for example, sendmail.cf.rpmsave). The upgrade process also creates a log of its actions in /root/upgrade.log.
As software evolves, configuration file formats can change, so you should carefully compare your original configuration files to the new files before integrating your changes.
Some upgraded packages may require the installation of other packages for proper operation. If you choose to customize your packages to upgrade, you may be required to resolve dependency problems. Otherwise, the upgrade procedure takes care of these dependencies, but it may need to install additional packages that are not installed on your system.
If the upgrade program does not detect a swap file that equals twice your RAM, it will ask you if you would like to add a new swap file. If your system does not have a lot of RAM (less than 32MB), you should probably add this swap file.