TrueNAS SCALETrueNAS SCALE Nightly Development Documentation
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An Uninterruptible Power Supply (UPS) is a power backup system that ensures continuous electricity during outages, preventing downtime and damage.

TrueNAS uses NUT (Network UPS Tools) to provide UPS support. For supported device and driver information, see their hardware compatibility list.

Report UPS bugs and feature requests to the NUT project.

Setting Up UPS Service

Connect the TrueNAS system to the UPS device. To configure the UPS service, go to System settings > Services, finding UPS, and click .

See UPS Service Screen for details on the UPS service settings.

TrueNAS Enterprise
TrueNAS High Availability (HA) systems are not compatible with uninterruptible power supplies (UPS).

Some UPS models are unresponsive with the default polling frequency (default is two seconds). TrueNAS displays the issue in logs as a recurring error like libusb_get_interrupt: Unknown error. If you get an error, decrease the polling frequency by adding an entry to Auxiliary Parameters (ups.conf): pollinterval = 10.

How do I find a device name? For USB devices, the easiest way to determine the correct device name is to set Show console messages in System Settings > Advanced. Plug in the USB device and look for a /dev/ugen or /dev/uhid device name in the console messages.
Can I attach Multiple Computers to One UPS? A UPS with adequate capacity can power multiple computers. One computer connects to the UPS data port with a serial or USB cable. This primary system makes UPS status available on the network for other computers. The UPS powers the secondary computers, and they receive UPS status data from the primary system. See the NUT User Manual and NUT User Manual Pages.