Dell PowerEdge T620 : How To Reduce FAN Speed with IPMI

Last updated: Oct 22, 2024

Not so recently, I had to replace Dell-certified mechanical hard drives with non-certified SSDs in a PowerEdge T620 server and was unpleasantly suprised to find that the fans were spinning noisly when inserted.

After a quick search, I discovered that this was a known problem and that Dell was unable to offer a solution… (source: https://www.dell.com/).

Thanks to god/internet, I found a post where a user was able to control the speed of the servers fans with ipmitool. So, big thank you to, tatmde: https://www.reddit.com/.

I'll simply publish here what I did in my situation.

🚨 Warning: Please note that changing the fan speed can cause overheating and damage components.

Enable IPMI over LAN

To control FAN speed via the network, we need to enable IPMI over LAN from IDRAC.

🚨 Warning: Enabling IPMI over LAN could be considered a security issue, as a remote station would have the ability to monitor the system's power status and gather information about the platform.

Connect to your iDRAC, go to iDRAC Settings > Network and enable IPMI Over LAN:

Dell PowerEdge T620 iDRAC Network Settings showing IPMI Over LAN enabled.

ipmitool utility

Installation under on GNU/Linux

Install the ipmitool software. This utility will enable us to communicate with IPMI.

From Debian you can use this command to install ipmitool:

root@host:~# apt-get install ipmitool

Using ipmitool

Check temperature

Get temperature information:

user@host:~$ ipmitool -I lanplus -H <iDRAC IP> -U <iDRAC user> -P <iDRAC password> sdr type temperature
Inlet Temp       | 04h | ok  |  7.1 | 21 degrees C
Temp             | 0Eh | ok  |  3.1 | 29 degrees C
Temp             | 0Fh | ok  |  3.2 | 35 degrees C

We can see the corresponding values in iDRAC:

Dell PowerEdge T620 temperature probes displaying CPU1, CPU2, and System Board Inlet temperatures.

Controlling FAN Speed

To disable manual/static fan control (automatic mode):

user@host:~$ ipmitool -I lanplus -H <iDRAC IP> -U <iDRAC user> -P <iDRAC password> raw 0x30 0x30 0x01 0x01

To enable manual/static fan control (manual mode):

user@host:~$ ipmitool -I lanplus -H <iDRAC IP> -U <iDRAC user> -P <iDRAC password> raw 0x30 0x30 0x01 0x00

Get the current fanspeed:

user@host:~$ ipmitool -I lanplus -H <iDRAC IP> -U <iDRAC user> -P <iDRAC password> sdr get Fan1 Fan2 | grep "Sensor Reading"
 Sensor Reading        : 1560 (+/- 120) RPM
 Sensor Reading        : 1560 (+/- 120) RPM

Set fanspeed to 1320 RPM (16%):

user@host:~$ ipmitool -I lanplus -H <iDRAC IP> -U <iDRAC user> -P <iDRAC password> raw 0x30 0x30 0x02 0xff 0x10

Set fanspeed to 1560 RPM (20%):

user@host:~$ ipmitool -I lanplus -H <iDRAC IP> -U <iDRAC user> -P <iDRAC password> raw 0x30 0x30 0x02 0xff 0x14

Set fanspeed to 2040 RPM (30%):

user@host:~$ ipmitool -I lanplus -H <iDRAC IP> -U <iDRAC user> -P <iDRAC password> raw 0x30 0x30 0x02 0xff 0x1e

Set fanspeed to 3000 RPM (50%):

user@host:~$ ipmitool -I lanplus -H <iDRAC IP> -U <iDRAC user> -P <iDRAC password> raw 0x30 0x30 0x02 0xff 0x32

Set fanspeed to 5040 RPM (100%):

user@host:~$ ipmitool -I lanplus -H <iDRAC IP> -U <iDRAC user> -P <iDRAC password> raw 0x30 0x30 0x02 0xff 0x64

Create ipmi service

I went crazy and decided to create a service that automatically regulates fan speed.

I'm going to detail here the different steps to set it up.

💡 Note: This script is tailored to my configuration.

Creating a system account

For security reasons, I've decided to run the service with a system account. Here's how to create a system account:

root@host:~# useradd --system --no-create-home ipmiservice

Create a log folder:

root@host:~# mkdir /var/log/ipmiservice

root@host:~# chown -R ipmiservice /var/log/ipmiservice

Create a bash script

Create the file /usr/local/sbin/ipmiservice.sh:

root@host:~# touch /usr/local/sbin/ipmiservice.sh

root@host:~# chown ipmiservice: /usr/local/sbin/ipmiservice.sh

root@host:~# chmod +x /usr/local/sbin/ipmiservice.sh

Edit the file /usr/local/sbin/ipmiservice.sh:

#!/bin/bash

#Stops script on errors, unset variables or failing pipeline
set -euo pipefail

#variables definitions
LOG=/var/log/ipmiservice/ipmi.log
IP="192.168.1.10"
PASSWORD='STp@ssw0rd!'

#functions
##Set Fan Speed, accept one argument to set speed
FanSpeed()
{
        ipmitool -I lanplus -H "$IP" -U root -P "$PASSWORD" raw 0x30 0x30 0x02 $1
}
##Get Temp values
GetValues()
{
        #Get motherboard, cpu1 and cpu2 temperature
        OUTPUT=$(/usr/bin/ipmitool -I lanplus -H "$IP" -U root -P "$PASSWORD" sdr type temperature | sed -e 's/Temp\(.*0Eh\)/Cpu1\1/' -e 's/Temp\(.*0Fh\)/Cpu2\1/')
        #Extract motherboard temp
        SB=$(echo $OUTPUT| awk -F'|' '{ print $5 $9 $13 }' | awk '{ print $1 }')
        #Extract cpu1 temp
        CPU1=$(echo $OUTPUT| awk -F'|' '{ print $5 $9 $13 }' | awk '{ print $5 }')
        #Extract cpu2 temp
        CPU2=$(echo $OUTPUT| awk -F'|' '{ print $5 $9 $13 }' | awk '{ print $9 }')
        #motherboard+cpu1+cpu2 temp
        LOG_TOTAL=$(($SB+$CPU1+$CPU2))
        #Get Fan1 speed
        FANS=$(ipmitool -I lanplus -H "$IP" -U root -P "$PASSWORD" sensor reading Fan1 | awk '{ print $3 }')
}

#set manual mode
ipmitool -I lanplus -H "$IP" -U root -P "$PASSWORD" raw 0x30 0x30 0x01 0x00

GetValues
echo "$(date "+%Y-%m-%d %H:%M:%S")" "MB : $SB | CPU1 : $CPU1 | CPU2 : $CPU2 | LOG_TOTAL : $LOG_TOTAL"

while :
do
        if [ "$LOG_TOTAL" -le 100 ] && [ $FANS -eq 1440 ]; then
                echo "$(date "+%Y-%m-%d %H:%M:%S")" "FAN speed : 1440, don't do anything" | tee -a "$LOG"
        elif [ "$LOG_TOTAL" -le 100 ] && [ $FANS -ne 1440 ]; then
                FanSpeed "0xff 0x12" #Set speed to 1440
                echo "$(date "+%Y-%m-%d %H:%M:%S")" "Set speed to 1440" | tee -a "$LOG"
        elif [ "$LOG_TOTAL" -gt 100 ] && [ "$LOG_TOTAL" -le 105 ] && [ $FANS -ne 1560 ]; then
                FanSpeed "0xff 0x14" #Set speed to 1560
                echo "$(date "+%Y-%m-%d %H:%M:%S")" "Set speed to 1560" | tee -a "$LOG"
        elif [ "$LOG_TOTAL" -gt 105 ] && [ "$LOG_TOTAL" -le 115 ] && [ $FANS -ne 2040 ]; then
                FanSpeed "0xff 0x1e" #Set speed to 2040
                echo "$(date "+%Y-%m-%d %H:%M:%S")" "Set speed to 2040" | tee -a "$LOG"
        elif [ "$LOG_TOTAL" -gt 115 ] && [ "$LOG_TOTAL" -le 130 ] && [ $FANS -ne 3000 ]; then
                FanSpeed "0xff 0x32" #Set speed to 3000
                echo "$(date "+%Y-%m-%d %H:%M:%S")" "Set speed to 3000" | tee -a "$LOG"
        elif [ "$LOG_TOTAL" -gt 130 ] && [ $FANS -ne 5040 ]; then
                FanSpeed "0xff 0x64" #Set speed to 5040
                echo "$(date "+%Y-%m-%d %H:%M:%S")" "Set speed to 5040" | tee -a "$LOG"
        fi
        sleep 30s
        GetValues
        echo "$(date "+%Y-%m-%d %H:%M:%S")" "MB : $SB | CPU1 : $CPU1 | CPU2 : $CPU2 | TEMP TOTAL : $LOG_TOTAL" >> "$LOG"
        echo "$(date "+%Y-%m-%d %H:%M:%S")" "FAN speed : $FANS" | tee -a "$LOG"
done

Creating a systemd service

We're now going to create a systemd service.

Create the systemd service:

root@host:~# vim /etc/systemd/system/ipmi.service

[Unit]
Description=ipmi t620 fan control
After=network.target

[Service]
Type=simple
User=ipmiservice
Group=ipmiservice
WorkingDirectory=/usr/local/sbin/
ExecStart=/usr/local/sbin/ipmiservice.sh
Restart=always

[Install]
WantedBy=multi-user.target

Enable the systemd service:

root@host:~# systemctl enable ipmi.service

Start the systemd service:

root@host:~# systemctl start ipmi.service

Check log output:

root@host:~# tail -f /var/log/ipmiservice/ipmi.log
2021-05-09 15:16:57 FAN speed : 1440, don't do anything
2021-05-09 15:17:32 MB : 22 | CPU1 : 37 | CPU2 : 40 | TEMP TOTAL : 99
2021-05-09 15:17:32 FAN speed : 1440, don't do anything
2021-05-09 15:18:04 MB : 22 | CPU1 : 38 | CPU2 : 40 | TEMP TOTAL : 100
2021-05-09 15:18:04 FAN speed : 1440, don't do anything
2021-05-09 15:18:36 MB : 22 | CPU1 : 39 | CPU2 : 40 | TEMP TOTAL : 101
2021-05-09 15:18:36 FAN speed : 1440, don't do anything
2021-05-09 15:18:37 Set speed to 1560
2021-05-09 15:19:09 MB : 22 | CPU1 : 38 | CPU2 : 40 | TEMP TOTAL : 100
2021-05-09 15:19:09 FAN speed : 1560