I have the following configuration:
- Intel NUC8I5BEK
- Samsung EVO 860 500GB M.2
- Crucial 16GB SO-DIMM 2400Mhz (single module installed in slot 1)
The BIOS is updated to the latest version (0048). I did not alter the bios configuration, so it is running with default settings.
I am running Ubuntu 18.10 Desktop with Docker and a couple of containers (HASSIO). The SSD is formatted as ext4. When I am using the NUC, there are no issues. However, when the device is idle, it randomly reboots, sometimes after 5 minutes, sometimes after 2 hours, but it has not been running 3 hours idle without rebooting. There is no crash report, no special errors logs.
I also tried running Ubuntu 18.04 Desktop LTS, but this has the same effect.
Partial output from "last reboot":
reboot system boot 4.18.0-10-generi Sun Oct 21 16:34 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 15:56 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 15:23 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 13:29 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 13:14 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 12:11 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 11:58 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 11:20 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 10:43 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 10:25 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 09:18 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 08:32 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 08:20 still running
reboot system boot 4.18.0-10-generi Sun Oct 21 08:03 still running
...
I did a benchmark on the SSD using the Disk application, and this executed without any issues. I also did some memory testing (with the command line tool as memtest86+ is not supported with UEFI), and found no errors.
I have no clue where to start looking, and the device is unusable as server this way. Any suggestions what I can try? Are they any BIOS settings I should be looking at?
I have been reading a lot of topics about similar problems (random reboots with Intel NUC). Often, it is due to a hardware fault (faulty adapter), and some people have suggested to reduce the memory speed to 2133 MHz - how can I achieve this?