I have a spike every morning at around 4:30 a.m. and I don’t know where it comes from.
Not from my cronjobs or any other planned tasks.
I have a setup on a Raspi4 with 4GB of RAM with iobroker, influxdb, grafana, nextcloud, apache, mysql
How does one best track such a thing?
My first idea is to enable full logging and then you wait 24 hours to collect some data and then you check your logs with a command like:
journalctl --since "2023-12-15 04:20:00" --until "2023-12-15 04:40:00"
to see what happend in the suspicious time frame.
My next idea would be to log system stats with grafana, but this is maybe a bit overcomplicated for this problem 
edit: oh you are already using grafana, maybe there is a way to track cpu utilization per process?!
there are cool monitoring tools for Grafana, InfluxDB and telegraf IoT — Raspberry Pi Container and System Monitoring with InfluxDB, Telegraf and Grafana | by Dorian Machado | Medium
But I don’t think it will log running process. Sooo get up at 4:20 to watch the system using htop 