Dell PowerEdge T620 : How To Reduce FAN Speed with IPMI

Last updated: Feb 8, 2022

Recently I had to replace Dell certified mechanical hard drives with uncertified SSD drives on a PowerEdge T620 server and was unpleasantly suprised to find that the fans were spinning noisly when inserted.

After quick research, I discovered that it was a known issue and that Dell wasn't able to offer any solution…

Thanks to god/internet, I also found a post where a user has been able to control the fan speed with the ipmitool. So, big thanks to, tatmde.

I will simply post here what I have done in my situation.

⚠️ Be advised that changing the fan speed may result in overheating and damage to the components. ⚠️

Enable IPMI over LAN

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

⚠️ Enable IPMI over LAN could be considered as security issue cause a remote station would have the capability to control the system's power state as well as being able to gather certain platform information. ⚠️

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

ipmitool utility

Installing on GNU/Linux

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

From a Debian you could use this command to install ipmitool :

root@host:~# apt-get install ipmitool

Using ipmitool

Check temperature

Get temperature informations :

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 :

Control FAN Speed

To disable manual/static fan control (auto 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 current Fan speed :

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 Fan speed at 1320 RPM (16%) :

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

Set Fan speed at 1560 RPM (20%) :

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

Set Fan speed at 2040 RPM (30%) :

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

Set Fan speed at 3000 RPM (50%) :

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

Set Fan speed at 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 got mad and decided to create a service that automatically regulates the speed of the fans.

I will detail here the different steps to set it up.

Note : This script is adapted to my own configuration

Create system account

For security reason I decided to run the service with system account. So let's create a system account :

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

Create log folder :

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

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

Create bash script

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

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

/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

Create systemd service

Now we will create a systemd service.

Create 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 systemd service :

root@host:~# systemctl enable ipmi.service

Start systemd service :

root@host:~# systemctl start ipmi.service

Check logs 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

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