I'm still fairly new to Linux Mint Debian and recently started seeing a "boot drive is full" warning whenever I start the computer. From what I've read, old kernel packages are probably filling the /boot partition. I enabled the Update Manager option to remove obsolete kernels and dependencies automatically several weeks ago, but the warning continues.
I'm considering using a command such as `sudo apt autoremove --purge`, but I'm not very comfortable with command-line tools yet. Is that a safe way to remove old kernels, and should I do anything else first? I understand that keeping the currently running kernel and at least one older working kernel is recommended. Would creating a Timeshift snapshot help, and what could go wrong if obsolete kernels are removed? Also, how can I tell whether only /boot is full or the entire Linux partition is running out of space?
3 Answers
Old kernels are normally safe to remove once they are no longer needed, but don’t remove individual files from /boot by hand. Kernel packages include files and package metadata that need to stay synchronized. Keep the kernel you are currently booted into plus at least one older known-good version. If the system can no longer boot or APT cannot run, a live USB may be needed to repair the installation.
If the packages were installed by APT, let APT remove them rather than deleting files from /boot manually. After checking that you’re currently running a kernel you want to keep, `sudo apt autoremove --purge` will usually remove unused kernel packages and their dependencies. Review the package list carefully before confirming, and make sure it does not propose removing the currently running kernel or every installed fallback kernel.
The automatic cleanup may only happen after a successful update and upgrade. If /boot is already too full, the update process might fail before it gets a chance to remove anything. First check whether /boot is a separate partition and how much space is available. You may need to free a small amount of space, then run the package manager’s repair/update process and let APT clean up the obsolete kernels.
That makes sense—I suspect the cleanup cannot run because the partition is already full. I’ll check the partition usage and avoid deleting kernel files directly unless I have no safer option.
A Timeshift snapshot can help restore system files, but it is not a substitute for keeping a usable kernel. It also may not protect you from every boot-partition problem, so checking the proposed APT removals is still important.