Raspberry PI 4 - 4gb - Main UI crashing

Dear all,
roughly 1 year ago i updated from a RPi 3b to a RPi 4 4gb using Openhabian.
I was running out of RAM memory back than and main ui was not usable anymore.
Unfortunately i do have the same problem now.
My frontend is “crashing” from time to time with a very strange behavior.
Normally i am using chrome on my windows machine to set up the mainui. But this is getting stuck sometime (openhab main ui not reachable or item values not loading). If i then change to EDGE, its working again, till it is “crashing” there, then chrome is working again.

Also i do have the feeling that my system is exhausted sometimes. Rules are not firing etc

My memory is used 1.8gb/3.74gb.
I think i do have a medium sized system.
Openhab, Zigbee2mqtt, Grafana, Influxdb is runing on the Rpi.
80 things, 711 items, 57 blockly rules (triggering rules, no high frequency rules).

To be honest, i dont want to buy a new server again and get the same problem in one year.

Can someone help to understand what the issue is?
Thank you!

Memory on the RPi is not the problem based on that screen shot of htop. You are not using swap and roughly half of your RAM is available should it be needed.

The crashing of the browsers is potentially caused by a memory leak in MainUI but is going to be challenging to find and diagnose. Monitor the amount of RAM consumed by the tab with MainUI open in Task Manager. Does it grow over time until it stops working?

What does htop look like when the rules and such are not responding?

Hello, thank you for your answer.
RAM memory doesnt seem to be the issue.
I am logging used RAM with the systeminfo binding.
This is a plot over the last 6 months, the spikes are reboots:

BTW: 0.7% is 70% used RAM :wink:

what do your logfiles ( openhab.log as well as syslog and journalctl ) show ?

Hi,
Were you able to solve the problem? I have a similar problem

Where can i find these log files?
Thank you