Sudden Memory Spike? Use journalctl + systemd‑coredump to Pin It Down
When a server’s RAM jumps from 30 % to 90 % in a matter of minutes, the first instinct is to kill processes, restart services, or add more memory. Those are quick fixes, but they don’t tell you why the spike happened. On a system that runs systemd, the combination of journalctl and systemd‑coredump gives a precise, timestamp‑aligned view of what went wrong. This post walks through a real‑world scenario, shows how to extract the relevant logs, and explains how to interpret the data so you can fix the root cause and harden the system against future incidents.