Maintain Old Kernels While Performing Kernel Upgrade - Redhat

Some might call me paranoid, but I get nervous when my package manager automatically removes a kernel.

================================================================================ Package Arch Version Repository Size ================================================================================ Installing: kernel x86_64 2.6.35.13-92.fc14 updates 22 M Removing: kernel x86_64 2.6.35.11-83.fc14 @updates 104 M   Transaction Summary ================================================================================ Install 1 Package(s) Remove 1 Package(s)

Redhat default behavior is to keep three kernels: the latest one and the two previous versions. However, this behavior may be counter-productive if you compile your own modules, or if you have compatibility issues with subsequent kernel versions.
You can change how yum handles kernel packages with some simple changes to your /etc/yum.conf. The installonly_limit option controls how many old packages are kept:

installonly_limit Number of packages listed in installonlypkgs to keep installed at the same time. Setting to 0 disables this feature. Default is ‘0’.

I disabled the functionality altogether by setting installonly_limit to 0:

#installonly_limit=3 installonly_limit=0

It’s important to keep in mind that you will need to purge these packages from your system yourself now. Kernel packages can occupy a fair amount of disk space, so make a note to go back and clean them up when you no longer need them.