Setup Unifi Dream Machine (UDM, UDM-SE, etc.) automatic fan speeds control to lower temps and increase hard drive lifespan.

udm_fancontrol_setup.sh

#!/bin/bash
# Installs and configures fancontrol to automatically run Unifi Dream Machine (UDM) fans harder & lower temperatures.
# 
# Context: Unifi equipment typically runs *very* hot from the factory unless you customize it.
# I don't want my hard drives to run as hot as they let them get by default (55ºC+), because it shortens lifespan (ideal temp is ~35-45C).
#
# Further Reading:
#   - https://linux.die.net/man/8/fancontrol
#   - https://community.ui.com/questions/Unifi-Dream-Router-fan-speed/1cb9cf18-e8a0-44b4-8402-ee9bac367bc0
#   - https://www.reddit.com/r/Ubiquiti/comments/13imgqj/udm_pro_fan_speed_is_this_normal/
#   - https://www.reddit.com/r/Ubiquiti/comments/lw4mjl/fan_speed_trick_on_udmp_not_working_on_190/
#   - https://github.com/heXeo/ubnt-fan-speed/issues/3
#   - https://ewpratten.com/blog/udm-fan/
#   - https://github.com/desbma/hddfancontrol
#   - https://unix.stackexchange.com/questions/499409/adjust-fan-speed-via-fancontrol-according-to-hard-disk-temperature-hddtemp

echo "[i] Here are your sensor readings before this script runs (for before/after comparison):"
sensors
hddtemp /dev/sda
hddtemp /dev/sdb

echo
echo
echo "[+] Installing fancontrol package using apt..."
apt-get update -qq
apt-get install -y fancontrol

echo
echo "[+] Setting up /etc/fancontrol config file (edit as-desired after this script completes)..."
tee /etc/fancontrol <<EOF
INTERVAL=1
DEVPATH=hwmon0=devices/platform/soc/fd880000.i2c-pld/i2c-0/i2c-4/4-002e
DEVNAME=hwmon0=adt7475
FCTEMPS=hwmon0/device/pwm2=hwmon0/device/temp1_input hwmon0/device/pwm1=hwmon0/device/temp3_input
FCFANS=hwmon0/device/pwm2=hwmon0/device/fan2_input hwmon0/device/pwm1=hwmon0/device/fan1_input
MINTEMP=hwmon0/device/pwm2=38 hwmon0/device/pwm1=38
MAXTEMP=hwmon0/device/pwm2=49 hwmon0/device/pwm1=49
MINSTART=hwmon0/device/pwm2=30 hwmon0/device/pwm1=30
MINSTOP=hwmon0/device/pwm2=15 hwmon0/device/pwm1=15
MINPWM=hwmon0/device/pwm2=10 hwmon0/device/pwm1=10
MAXPWM=hwmon0/device/pwm2=255 hwmon0/device/pwm1=255
EOF

echo "[*] Restarting fancontrol service to apply changes..."
systemctl restart fancontrol

sleep 1
echo

echo "[√] Complete. Check the sensor readings to make sure fans are spinning faster:"
sensors
hddtemp /dev/sda
hddtemp /dev/sdb

# Typical Values on my machine after setting this up:
#
# root@UDM ~# sensors
#
# adt7475-i2c-4-2e
# Adapter: i2c-0-mux (chan_id 3)
# in1:         908.00 mV (min =  +0.00 V, max =  +2.99 V)
# +3.3V:         3.29 V  (min =  +2.96 V, max =  +3.63 V)
# fan1:        5288 RPM  (min =    0 RPM)
# fan2:        2349 RPM  (min =    0 RPM)
# fan3:           0 RPM  (min =    0 RPM)
# fan4:           0 RPM  (min =    0 RPM)
# temp1:        +42.5°C  (low  = -63.0°C, high = +191.0°C)
#                        (crit = +100.0°C, hyst = +96.0°C)
# Board Temp:   +42.0°C  (low  = -63.0°C, high = +191.0°C)
#                        (crit = +100.0°C, hyst = +96.0°C)
# temp3:        +43.8°C  (low  = -63.0°C, high = +191.0°C)
#                        (crit = +100.0°C, hyst = +96.0°C)
#
# root@UDM ~# hddtemp /dev/sda
# /dev/sda: KINGSTON OM4P0S3128B-A0: 49°C
#
# root@UDM ~# hddtemp /dev/sdb
# /dev/sdb: WDC WD101EMAZ-11G7DA0: 45°C

Hello friends,

Here is the solution to have this working even after reboots or updates. Initially was thinking to either SSH from other machine (as suggested by @pirate or to run Ansible every day (now knowing if the DM was reset or not). But finally, I found a more elegant solution:

1. From unify-utilities install UDM Boot Script

Follow these instructions https://github.com/unifi-utilities/unifios-utilities/blob/main/on-boot-script-2.x/README.md . You can build the package yourself or just run the curl | bash command (not recommended, but at least check the script first).

This will create a /data/ folder which conveniently has an on_boot.d directory

2. Run @pirate's script (I've adapted to make it run automatically

root@Dream-Machine:~# cat /data/on_boot.d/10-fan-control.sh 
#!/bin/bash

apt-get -qq update
apt-get -qq install -y fancontrol tmux

cat <<EOF > /etc/fancontrol
INTERVAL=1
DEVPATH=hwmon0=devices/platform/soc/fd880000.i2c-pld/i2c-0/i2c-4/4-002e
DEVNAME=hwmon0=adt7475
FCTEMPS=hwmon0/device/pwm2=hwmon0/device/temp1_input hwmon0/device/pwm1=hwmon0/device/temp3_input
FCFANS=hwmon0/device/pwm2=hwmon0/device/fan2_input hwmon0/device/pwm1=hwmon0/device/fan1_input
MINTEMP=hwmon0/device/pwm2=38 hwmon0/device/pwm1=38
MAXTEMP=hwmon0/device/pwm2=49 hwmon0/device/pwm1=49
MINSTART=hwmon0/device/pwm2=30 hwmon0/device/pwm1=30
MINSTOP=hwmon0/device/pwm2=15 hwmon0/device/pwm1=15
MINPWM=hwmon0/device/pwm2=10 hwmon0/device/pwm1=10
MAXPWM=hwmon0/device/pwm2=255 hwmon0/device/pwm1=255
EOF

systemctl restart fancontrol

3. Profit

For the base UDM it's slightly different as it only has one fan and the sensor chip is not the same. Also it must run a little hotter as the fan ramps up and is rather noticeable.

INTERVAL=2
DEVPATH=hwmon0=devices/platform/soc/fd880000.i2c-pld/i2c-0/0-004c
DEVNAME=hwmon0=lm63
FCTEMPS=hwmon0/device/pwm1=hwmon0/device/temp1_input hwmon0/device/pwm1=hwmon0/device/temp2_input
FCFANS=hwmon0/device/pwm1=hwmon0/device/fan1_input
MINTEMP=hwmon0/device/pwm1=40
MAXTEMP=hwmon0/device/pwm1=64
MINSTART=hwmon0/device/pwm1=30
MINSTOP=hwmon0/device/pwm1=15
MINPWM=hwmon0/device/pwm1=10
MAXPWM=hwmon0/device/pwm1=255

Sensors output;

sensors
lm63-i2c-0-4c
Adapter: Synopsys DesignWare I2C adapter
fan1:        6490 RPM  (min = 4205 RPM)
temp1:        +63.0°C  (high = +70.0°C)
temp2:        +59.2°C  (low  =  +0.0°C, high = +70.0°C)
                       (crit = +93.0°C, hyst = +83.0°C)