So, I guess what I'm having is a hang. Seems to be when there is heavy network traffic. Everything was fine for years, then I recently upgraded to Debian stretch 9.1. It stated about a week after that. If I turn off networking, it seems to not have any problems. Doesn't hang.
Its got all stock settings, no overclocking.
Looking at the logs, their will be a bunch of activity, and it looks like the networking will start going up and down. Many pages of stuff then it just stops. I was thinking I was just losing the network at first (it's headless) but on restarts the log is empty from the time it stopped being on the network till I reboot it. So that's sometimes a day or so. That makes me think it's hanging. All the lights are still on, and networking led flashes.
The only other new thing was the fan locked up. It came with my case so I always used it. When I went to see what was up the first time it did this, the fan was making a grinding noise and moving about 30 rpms. And burned the heck out of me when I touched it.
My first thought was it was overheating due to the fan throwing so much heat. So I removed the fan, got the pi up and working. Logged into it, checked the logs, temp, and what not. All seemed fine. I ordered up a new fan on Amazon and then noticed I couldn't log in again. Kept resetting it, and it would last 5 to 30 mins then hang again. I use it as vpn server, so I turn off the clients so it doesn't have any traffic, and it will stay up for days. When on, it has a good amount of traffic.
I was seeing lots of stuff about Sweet32 in the logs. Thought that might be it, so I took care of that, stopped using BF and started using 256. Got everything up and running, all seemed well. Then lost it again 4 hours later.
It seems either the traffic, or openvpn itself triggers it.
The only other thing I've seen in the log is it complaining about a self detected hang on a cpu. That was the last time it hung. I'll do some more testing and get it to hang again, see if that is in the logs.
Mainly I'm seeing if anyone has seen this before? Wanting to get input before I buy a new power supply and SD card. I'm tempted to just buy a new pi.
I'm just holding out hope someone else has seen this after upgrading to stretch, so I don't just throw new hardware at the problem for no reason.