I'm not quite sure what's causing it, but I've added the diagnostics after the last reboot, as well as the syslog server csv export from the whole of today up until the reboot event. Hopefully this is enough to at least give a direction?

I don't want to sway opinions on what it might be, but I do have a feeling it might be to do with drives shutting down due to overheating.

I got the LincStation S1 due to my tower system being RMA'd, and I thought this would be a good temp/possible permenant solution. So I've migrated my 4x HDDs (Seagate Exos) and 2x NVME SSDs for cache over to the S1.

It works fine mostly, but it does seem to be quite warm all the time and their cooling solution doesn't seem to be living up to expectations. I THINK (can't be certain) that the reboots have happened mostly when all drives are active, such as when a parity check is happening, since that runs all drives at once and drives often get to an uncomfortable ~45 degrees.

But hopefully the logs reveal more?

All_2025-9-7-13_13_13.csv unrais-diagnostics-20250907-1303.zip

Nothing relevant logged on the syslog, and a server rebooting on its own is almost always a hardware problem.