How Many Linux Kernels Should You Keep?

As an open source operating system, Linux based Ubuntu is undergoing constant changes. As new features are built-in, security flaws repaired, and bugs fixed, there is a constant stream if updates to the component programs that are installed on computers running Ubuntu Linux. One component that may end up with multiple versions of its software residing on a computer running Ubuntu Linux is the kernel. The Linux kernel is the first thing that is loaded when your Ubuntu PC turns on.

The main job of the Linux kernel is to stay out of the way of the other programs running on your computer. Even though the Kernel must stay out of the way, it still has a very important job to perform. The Kernel assigns resources to programs, and decides whether to ten hardware on or off, based on requests made by programs running on your computer. The kernel also determines which drivers should be used to get your hardware to work properly. It is common practice for Ubuntu developers to issue several versions of the Linux kernel during the support lifetime of your Ubuntu computer. Thus, over time, several versions of the kernel may start to pile up on your computer's hard drive.

Why more than one Kernel is important.

It is possible a Linux kernel to become corrupted. This can occur due to sectors going bad on your disk drive, or even a due to corruption during an update. If this occurs, then it will not be possible to run your operating system. Since the Linux kernel is a self contained program running on your computer it is possible to switch out kernels for another one. Thus, it is always good practice to keep an extra kernel or two in case your main one becomes corrupted.

When disk space becomes a concern.

Some Ubuntu Linux users like to partition their disk drives. For example, it may be advantageous to place user files on a separate /home partition so that user files remain untouched when fresh installs are performed on the operating system. The Kernel resides in /boot and some system administrators also like to have a separate partition for /boot. If multiple patches for Linux kernels are issued, then you may find that /boot is filling up. You can check your disk space and configuration be issuing the df -f command at a console prompt.

If your /boot or / partition is starting to fill up then it may be time to get rid of those extra Linux Kernels. Although it is quite safe to remove multiple Linux kernels, you should think carefully about how many extra kernels you want on your system. A good rule of thumb used by many system administrators it to keep at least two versions of the Linux kernel. The primary, and the backup. Some administrators will keep a third kernel.