How to turn iDRAC fan speed down if server is unneccesarely loud:

apt update -y && apt upgrade -y

apt install sudo -y

sudo apt install ipmitool -y

disable automatic fan speed setting:

ipmitool raw 0x30 0x30 0x01 0x00

set fan speed:

ipmitool raw 0x30 0x30 0x02 0xff <hex>, for example 0x14 for 20%

enable automatic fan speed again when wanted:

ipmitool raw 0x30 0x30 0x01 0x01