Disk‑full crashes are the most common reason a VPS goes from “alive” to “dead” overnight.
A log file or a database that blows past the allotted space will make the kernel refuse
any further writes, and every process that needs to touch the disk will start failing.
If you’re running a website, mail server, or database, that’s a service outage you can’t afford.
The silver lining? A handful of LVM tricks and a tiny monitoring script can get you back up in minutes and keep future incidents at bay.
Below I walk through a real‑world scenario on a Debian‑based VPS, but the ideas carry over to any distro that uses LVM and systemd.