I installed OpenWRT 18.06.4 in my Ubiquiti EdgeRouter X a couple of weeks ago. I have three devices conected to it running an OpenVPN client, Adblock and CollectD serving metrics to a Raspberry Pi every 30 seconds.
The router started to work really cool (no heat at all, seriously) but I suddenly experienced a throughput drop because the server that I was connected to started to get overloaded.
I've connected to the router through ssh, changed the ovpn and restarted the tunnel. I didn't do anything else. A couple of hours later I touched the router and it was hot (like really hot).
The device was emitting constant heat for the next two days and suddenly it started to cool down again, without doing anything.
When the device worked with that low temperature I was torrenting and streaming a Netflix show. The network is always transmitting and receiving data.
Now, yesterday I experienced the same: slow VPN server. I stopped OVPN late night and left it down. When I woke up today, guess what: hot router again. It's still hot at the time of writing this.
I've monitored those temp spikes with htop and I don't see any significant CPU / Memory usage. It's never in constant use and I haven't saw the router crossing the 50% mark in any of it's cores, even when under "heavy load" with data tx/rx.
I don't understand this and I want to. How can I diagnose this? Which service is the culprit?
I'm attaching an htop screenshot:
I really appreciate any insights and help for diagnosing this.