Supermicro Fan Control

I was inspired by a fan control perl script posted on the FreeNAS forum for Supermicro motherboards. This script will adjust the fan profile based on drive temperature. It is intended to be run as a cronjob every 5 minutes.

#!/usr/local/bin/python3
import re
import subprocess

DRIVE_PREFIX = 'da'
DRIVE_COUNT = 8

MAX_TEMP = 48
THRESHOLD = 1

def get_temp(idx):
        p = subprocess.Popen(['smartctl', '-a', '/dev/%s%d' % (DRIVE_PREFIX, idx)], stdout=subprocess.PIPE)
        data = p.communicate()
        m = re.findall(r'Current Drive Temperature:.*(\d\d) C', data[0].decode('utf-8'))
        return int(m[0]) if m else None

def set_speed(val):
        subprocess.Popen(['ipmitool', 'raw', '0x30', '0x45', '0x01', '0x0%d' % val]).communicate()

def main():
        highest = 0

        for x in range(0, DRIVE_COUNT):
                t = get_temp(x)
                if t and t > highest: highest = t

        if highest >= MAX_TEMP:
                print('Setting speed to full')
                set_speed(1)
        elif MAX_TEMP - highest > THRESHOLD:
                print('Setting speed to standard')
                set_speed(0)

if __name__ == "__main__":
        main()
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