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Configuring UPS Service

  2 minute read.

Last Modified 2022-06-08 12:29 EDT

TrueNAS uses NUT (Network UPS Tools) to provide UPS support. When the TrueNAS system is connected to a UPS device, configure the UPS service by going to Services, finding the UPS entry, and clicking edit edit icon.

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See UPS Screen for more information on UPS settings. Some UPS models can be unresponsive with the default polling frequency. This shows in TrueNAS logs as a recurring error like libusb_get_interrupt: Unknown error. If this log error occurs, decrease the polling frequency by adding an entry to Auxiliary Parameters (ups.conf): pollinterval = 10. The default polling frequency is two seconds.

upsc(8) can get status variables like the current charge and input voltage from the UPS daemon. Run this command from the Shell using the syntax upsc ups@localhost. The upsc(8) manual page has other usage examples.

upscmd(8) can send commands directly to the UPS, assuming the hardware supports sending the command. Only users with administrative rights can use this command. These users are created in the Extra Users field.

For USB devices, the easiest way to determine the correct device name is to set Show console messages in System > Advanced. Plug in the USB device and look for a /dev/ugen or /dev/uhid device name in the console messages.
A UPS with adequate capacity can power multiple computers. One computer is connected 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 secondary computers are powered by the UPS, but receive UPS status data from the primary computer. See the NUT User Manual and NUT User Manual Pages.

See UPS screen for more information on setting up a UPS.