Setting up the UPS NUT service to shut down a standalone FreeNAS system is straightforward. But things become more interesting when you have multiple systems, especially when those systems are All-In-One (AIO) servers with FreeNAS running as a virtual machine on VMware's ESXi. In this case you don't want to shut down FreeNAS directly. Instead, you want to shut down ESXi and let it shut down all of its virtual machines, including FreeNAS.
If you're running ESXi v4.x/5.x/6.x, you're fortunate...
UPS setup for multiple All-In-One (FreeNAS-on-ESXi) servers on the same UPS
If you're running ESXi v4.x/5.x/6.x, you're fortunate...
UPS setup for multiple All-In-One (FreeNAS-on-ESXi) servers on the same UPS