Created Samstag 04 Juli 2020
Let a harddrive sleep.
Create a file in rules.d like 69-hdparm.rules. The number is the execution priority. The higher the later.
ACTION=="add", KERNEL=="sd[a-z]", ENV{ID_SERIAL_SHORT}=="WD-WX11D4431992", RUN+="/usr/bin/hdparm -S 241 /dev/%k"
ATTENTION
In case of Ubuntu use /etc/hdparm.conf instead.