I was able to get it to reboot, but it seems Unraid thought it was an unclean shutdown, as parity check is running.
Thanks, your description of cache disk full makes sense. Do you see any obvious errors that would prevent me from rebooting the server in a normal amount of time. For a bit more info, I'm having some performance issues (slow/no downloads) with my nzbget container that I'm troubleshooting.