Periodic system load peaks

[gordaansiosa]

Hello,
It may be a dumb question, sorry about that. I am just starting with truenas.
Since two days ago, it is showing periodic system load peaks, please see below. That wasn't the case before. And I haven't install any new apps.

I cannot pin point what is causing it. I have tried to check it via Netdata and the command line, but I can only get hat far. They show that dockerd/containers and "others" are causing it.
when trying k3s kubectl top I get "error: Metrics API not available"

How can I troubleshoot it?
Thanks in advance