Thanks for the info.
This morning I have tested the following, Unraid (R210ii) as NUT master, Synology as NUT slave, PFsense as NUT slave.
Same issue occurs, if not a few minutes worse. Setup NUT on unraid to shutdown after 1 minute on battery. pfsense seems to start it's shutdown sequence at the same time. Synology, I set to after 45 seconds on battery.
Synology and pfsense automatically go off nicely within 2 minutes of power being lost to UPS. UnRaid hangs at both the "Waiting up to 90 seconds for graceful shutdown..." and "Forcing Shutdown". For around 12-15 minutes before powering off. If I "Shutdown" in the gui, the R210ii is off within 2 minutes.
I can try pfsense being the NUT master, but with similar experiences being had with synology being the NUT master, and now same with unraid server being NUT master, I'm inclined to believe it wont make a difference. Something in the NUT unraid plugin shutdown sequence is causing the delay.
Anyway I can troubleshoot this lengthy delay?