This thread is confusing, so I'll try a generic how-to description...
First, disable the auto spin-down timer on the JMS controller (-t 0) and reboot to activate it.
Having the controller manage harddisk spin-down is not a good idea, only the OS and applications know when a disk is no longer (or not) needed and the OS/apps ask a harddisk to please spin-down and the hard-disk then knows what to do. No need for a controller to do that at an arbitrary time, sitting as a middle man between the two. That the ODROIDs ship with a preprogrammed spin-down timer enabled is not a good default IMHO.
Unmount all partitions of the harddisk.
Make sure that no process accesses the harddisk in any way (e.g. a background script that checks SMART status at certain time intervals).
If you are sure nothing accesses the disk anymore, spin it down manually with "hdparm -y". This lets it spin down and upon next access it spins up again.
Do not use hdparm -Y, it is stronger. It spins down and some disks go to hard sleep, only to be awoken again by a hard bus reset. What state a disk is in after being jolted awake this way is different from vendor to vendor, so it's not fun to guess how they will wake up.
Does the disk spin-down with "hdparm -y"?
If no - sorry, this disk ignores the command. I once had a Toshiba one that did this...
If the disk spins down, but immediately spins up again, or after a few seconds, then you still have a process that tries to access it. Find the process and kill it.
Does it stay spin-downed for a longer time? Good, that is what is expected when no accesses happen.
Spin disk up again, for example by reading the SMART status.
Set the disk to auto spin-down when 30mins idle: hdparm -S 241
Try it, measure the 30 mins.
If the drive does not spin-down - are you sure there is no process accessing it? Send it to sleep manually again (hdparm -y) and wait longer to see whether something wakes it up.
If it spins down earlier than 30 mins - was the timer on the JMS disabled? Is the OS doing it with some power management setting? I also once had a disk that had a hardcoded 3 min idle spin-down which could not be changed by normal software commands - very annoying product.
If the 30mins work, good, try again with e.g. 2 hours, hdparm -S 244.
If 30mins work and 2 hours don't, then you maybe have an hourly script that accesses the disk (e.g. hourly SMART status check)
If the 2 hours work, good, go from there, your disk works as commanded, the rest is an OS/apps problem.
hdparm -B may have an effect. Some disks ignore -B totally, some do behave differently when running on -B 255 vs -B 128/254. I have some HGST disks that behave weirdly as they boot with -B 128 default, but if I set them to -B 255 in my bootup scripts then they behave as they are commanded (above hdparm commands)
The Seagate Ironwolf disks are NAS drives, designed to run 24/7? They probably have more sophisticated settings available, check out the https://github.com/Seagate/openSeaChest
project. I never tried these myself...
Hope this helps someone somehow.... :-)