Fan speed PID controller based on hard drive temperature
This script is meant for storage servers with lots of (spinning) hard drives. It regulates the chassis (PWM) fan speed based on the hard drive temperature.
The script is intended for people who build large storage servers used in an environment (at home) where noise matters.
The hard drive temperature is monitored through either SMART or the MegaCLI tool used by LSI-based HBA controllers.
Fan speed is governed by PWM fan controls and sensors as supported by Linux under /sys/class/hwmon, such as /sys/class/hwmon/hwmon2/device/pwm2.
This script has been updated to handle multiple PWM devices.
For example, if you have 24 drives in a chassis, this script checks the temperature of each drive. The temperature of the hottest drive is used to determine if the chassis fans need to run faster, slower or if they should stay at the same speed.
the PID controller makes sure that an optimal fan speed is found to keep the system at a maximum of - in my case - 40C.
The script logs internal variables to syslog by default.
Temp: 40 | FAN: 51% | PWM: 130 | P=0 | I=51 | D=0 | Err=0 | Temp: 40 | FAN: 51% | PWM: 130 | P=0 | I=51 | D=0 | Err=0 | Temp: 40 | FAN: 51% | PWM: 130 | P=0 | I=51 | D=0 | Err=0 | Temp: 40 | FAN: 51% | PWM: 130 | P=0 | I=51 | D=0 | Err=0 | Temp: 39 | FAN: 43% | PWM: 109 | P=-2 | I=50 | D=-5 | Err=-1 | Temp: 39 | FAN: 47% | PWM: 119 | P=-2 | I=49 | D=0 | Err=-1 | Temp: 40 | FAN: 54% | PWM: 137 | P=0 | I=49 | D=5 | Err=0 | Temp: 40 | FAN: 49% | PWM: 124 | P=0 | I=49 | D=0 | Err=0 | Temp: 40 | FAN: 49% | PWM: 124 | P=0 | I=49 | D=0 | Err=0 | Temp: 40 | FAN: 49% | PWM: 124 | P=0 | I=49 | D=0 | Err=0 |
This will give you output on the console:
The disk temperature is read through 'smartctl' (part of smartmontools). Temperature can also be read through LSI-based HBAs managed by MegaCLI. You must edit the main function to switch between these two options.
The script performs a poll every 30 seconds by default.
I'm using this script myself to govern the fan speed of my [storage server][NAS].
- Copy the configuration file in /etc/
- Copy the executable in /usr/sbin or anywhere you want
- Make sure the script is executed on boot.