Patches can introduce a significant amount of new software into our systems. Some of the scenarios we discuss in this chapter introduce hundreds of megabytes of new software into our systems. This is not without risks. The risks I am thinking of include the possibility that your system will fail during a patch installation. In such a situation, your kernel may have been in the process of being updated, but it is left in an inconsistent state. Your system may no longer be able to boot. Even using an alternative kernel may fail if some critical software libraries were in the process of being updated. These and other risks need to be understood before proceeding with a patching exercise. Remember these are some key points before embarking on any patching exercise:
Ensure that you have a full, consistent backup of your entire system. A recommended minimum is the use of a make_nettape_recovery , whereby the operating system disks can be recovered quickly in the event of a catastrophic failure.
Read all the associated documentation relating to the patches to be loaded. This includes the files affected by the patch. The size of the patch will also be listed. This additional space will be necessary under the /var filesystem in order to save the current version of the affected software.
When performing an installation of any patches, ensure that all Warnings and Errors are investigated and resolved before proceeding with the installation.
Adhering to these simple guidelines will help minimize any failures experienced during the patching exercise.
