I have a problem with my RPi4B-4GB RAM model in that it seems to lock up approximately once every 1-2 days.
What happens is that suddenly my PuTTY window connected to the RPi4 plings and shows a loss of network connection to the RPi.
The RPi is not rebooting, it seems just to have hung...
Waiting a while does not help, only power cycling it does.
Now I wonder if there is a logfile or similar that I can check to find out when exactly it locked up or other similar information?
I am running a fully updated Raspbian Buster (september release) and I have enabled SSH and VNC. Apache is installed but not yet set up so only the default Debian Apache page is served. I have also installed OpenVPN as a client (no server enabled) and FreePascal/Lazarus as development system.
Networking is through wired Ethernet and also WiFi into the same local LAN. So there are two connections.
I have now used the GUI to "Turn off WiFi".
This behavior is annoying since I plan on building a monitoring system intended to run unattended in a remote location only connected by mobile Broadband to the Internet. The system is to be controlled from the RPi box, but it must not ever hang like this.
Is there a hardware watchdog built into the RPi that can be used to at least reboot the RPi if it locks up?
If so how do I enable this?
Or is there some other way to ensure that it stays working?
I have used all models of RPi (B type) since the very first launch back in 2012 and I have deployed 6-7 units on various locations acting as OpenVPN servers for access to their networks and also as temperature logging units and I have never before come across one that locks up like this. They have been rock solid...