TrueNAS CORETrueNAS CORE Nightly Development Documentation
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UPS Screen

An uninterruptible power supply is a hardware device that provides a backup source of power in the event of a power outage. Use the UPS services screen to configure a UPS for your TrueNAS.

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

SAVE activates after all required fields are populated.

CANCEL exits without saving and returns you to the Services screen.

UPS Options
Figure 1: UPS Options (Top)

General Options

IdentifierType a description for the UPS device. You can use alphanumeric, period (.), comma (,), hyphen (-), and underscore (_) characters. This is a required field.
UPS ModeSelect mode from the dropdown list. Master is an option if the UPS plugs directly into the system serial port. Select Slave to have this system shut down before the master system. The UPS remains the last item to shut down. See the Network UPS Tools Overview.
DriverSelect the device driver from the dropdown list. See the Network UPS Tools compatibility list for a list of supported UPS devices. This is a required field.
Port or HostnameSelect the serial or USB port connected to the UPS from the dropdown list. Options include a list of ports on your system and auto. Select auto to automatically detect and manage the USB port settings. Enter the IP address or host name of the SNMP UPS device when selecting an SNMP driver. If the UPS Mode field is set as Master, this is a required field. If set to Slave this field is not required.


Monitor UserEnter a user to associate with this service. Keeping the default is recommended.
Monitor PasswordChange the default password to improve system security. The new password cannot include a space or #.
Extra UsersEnter accounts that have administrative access. See upsd.users(5) for examples.
Remote MonitorSelect to have the default configuration listen on all interfaces using the known values of user: upsmon and password: fixmepass.
UPS Options
Figure 2: UPS Options (Bottom)


Shutdown ModeSelect the battery option to use when the UPS initiates shutdown. Dropdown list options are UPS reaches low battery or UPS goes on battery.
Shutdown TimerEnter a value in seconds for the UPS to wait before initiating shutdown. Shutdown does not occur if power is restored while the timer is counting down. This value only applies when Shutdown Mode is set to UPS goes on battery.
Shutdown CommandEnter a command to shut down the system when either battery power is low or the shutdown timer ends.
Power off UPSSelect for the UPS to power off after shutting down the system.


Send Email Status UpdatesSelect to enable sending messages to the address defined in the Email field.
EmailEnter any email addresses to receive status updates. Separate entries by pressing Enter.
Email SubjectEnter the subject for status emails.

Other Options

No Communication Warning TimeEnter the number of seconds to wait before alerting that the service cannot reach any UPS. Warnings continue until situation resolved.
Host SyncLength of time in seconds for upsmon to wait while in master mode for the slaves to disconnect. This applies during a shutdown situation.
DescriptionEnter a description for this service.
Auxiliary Parameters (ups.conf)Enter any extra options from ups.conf.
Auxiliary Parameters (upsd.conf)Enter any extra options from upsd.conf.