Gradual Internet Performance Degradation since upgrading to 26.7.x

[tonys]

Ever since upgrading from 21.x to 26.7.x, I've been experiencing gradually deteriorating internet performance. Specifically, after a router reboot, internet performance is great but over a period of a few hours it begins slowing down. LAN devices have trouble accessing the internet and at times, they can't connect at all. The OPNSense web GUI also slows down simultaneously with the internet slowdown to the point where I can't open the GUI at all. Typically, I log into an SSH shell and restart the web gui which sometimes helps but not always. Eventually, the only solution is a complete reboot of the router which then brings performance back to normal for a few hours and this cycle repeats.

The temporary fix I've found so far is to enable Proton VPN on the affected LAN devices which restores internet performance but does nothing for the OPNSense web GUI. After sitting overnight, the web GUI becomes somewhat responsive again but still slow and gradually degrades again after a few hours. Unfortunately, internet performance remains severely degraded and almost useless without the external VPN turned on. Rebooting the router restores LAN internet performance but only for a few hours.

I've noticed posts here about similar issues with earlier OPNSense releases after upgrades but haven't seen anything about this happening after upgrading from the final 21.x release to  26.7.x. Is anyone else experiencing this?

I'm currently running OPNSense 26.7.6 on a Protectli VP2420 with 16GB of ram. There are no OPNSense processes hogging CPU time, free ram is running about 13GB, the firewall state table hovers in the low 300's, and unnecessary services (ClamAV, Netflow) are turned off which helps a bit but not permanently. I suspect Unbound is the culprit since my IoT and Guest networks bypass Unbound and run fine with DNS servers 8.8.8.8 and 1.1.1.1. Only the LAN is affected because Unbound passes its traffic to Quad9 servers. Unbound logs show all DNS traffic going out since I added bypasses from servers blocked by Steven's Blacklist.

Gemini and Grok recommend I wipe the Protectli flash and install OPNSense 26.7 from scratch, and then restore the router from the backed up config.xml but I don't know if this will work. Advice would be appreciated as I've been battling this slowly degrading performance cycle for a couple of months.

[nero355]

There are no OPNSense processes hogging CPU time

Post your 'top' output anyway :
- One after reboot.
- One when everything has slowed down.

And if you haven't already : Disable HostWatch

I suspect Unbound is the culprit since my IoT and Guest networks bypass Unbound and run fine with DNS servers 8.8.8.8 and 1.1.1.1. Only the LAN is affected because Unbound passes its traffic to Quad9 servers. Unbound logs show all DNS traffic going out since I added bypasses from servers blocked by Steven's Blacklist.

A while ago someone had issues because the Unbound Logging Level was set too high and the SSD could not keep up with it IIRC so you could take a look at that too!