There is sound “clack” you can hear from the HDD when the system almost the end of power-off process.
It is caused decrease lifecycle to your HDD and could be damaged in the worst case.
I think that it needs lots of time to fix that behavior. so I recommend using this script as a workaround.
This script makes your HDD safely to park. no sound, no increases the SMART attribute Power-Off_Retract_Count at all.
I have checked some kind of HDDs with no issue. But I'm not sure that it works 100 percent to any kind of HDDs.
Thank you @Nominal Animal for giving us your idea from the odroid forum. External Link

Applied to HC1/HC2.
Download the script and install.

root@odroid:~# sudo apt-get install hdparm
root@odroid:~# wget https://dn.odroid.com/5422/script/odroid.shutdown
root@odroid:~# sudo install -o root -g root -m 0755 ./odroid.shutdown /lib/systemd/system-shutdown/odroid.shutdown

S.M.A.R.T Monitoring Tools show us lots of information for SMART Disks.
And there are some attributes has defined by the vendors.
so if you want to know the exact meaning of attribute, you should check first the documentation your vendor provided about your disks.

Reported from our forum, another case shutdown script doesn't work well.
Please check this link, you may have luck.
Thanks @FanDjango.