How to best troubleshoot rare and short CPU spikes

[9axqe]

Since a week, from time to time, once a day or once every two days, it appears opnsense is locking up.

Symptoms are:
* it lasts for 10-20s
* network down – I can't ping outside anymore, I can't ping opnsense anymore
* Home Assistant looses connection to opnsense, when opnsense API comes back, CPU is still very high.

By the time I log into the GUI, CPU is back to normal.

I have a DEC695. What would be the best approach to understand what is happening during this brief moments?

[newsense]

Keep an SSH session running with top or better yet htop (from mimugmail's repo)

Unsure what CPU that DEC has, but these freezes are likely due to some large updates that may take a bit to process, either Unbound DNSBL or similar from AGH, or aliases. If having many aliases with lists that auto update make sure they don't start at the same time as well

[9axqe]

Thanks. After troubleshooting, it appears it's a layer 1 issue before the opnsense router, I'm going to have a lot of fun... =\