Please add a watchdog process to make sure any software hangs or lockups don't disable the NAS.
I recently did a remote reboot and the NAS just locked up with NO FAN! Needless to say, I came back on site and the unit was extremely hot, luckily there was no damage. Typically the processor should have a hardware watchdog facility built in, if not then either a software watchdog or just default the fan speed to high on any system change before its set and immediately change it back on confirmation. This would at least guarantee the unit is getting some airflow in the event the system locks up.