HDD Spin down recently not working since a few days

check, which processes making reads or writes to the device with command

btrace -a fs /dev/disk/by-id/wwn-0x50014ee2ae42a608 | egrep -e ' +I +[RW]A? '
btrace -a fs /dev/sda | egrep -e ' +I +[RW]A? ' # -> relative device naming (sdx) can vary with every reboot

# btrace is installable with package blktrace --> https://www.man7.org/linux/man-pages/man8/btrace.8.html 

Quote from hg6807

Code

pi@RasPi4:~ $ sudo btrace -a fs /dev/disk/by-id/wwn-0x5000c500c3b6ca25 | egrep -e ' +I +[RW]A? '

Nothing appears, no further commands possible, HDD still at spinning

press Ctrl+C, to abort
if nothing comes up here, then there is no access to the disk as desired.

some devices (as my WesternDigital Green Line) will never go into spindown by itself. you can force them to spin down by hdparm -y <DEVICE-ID> and they will spin up if accessed.

Also noticing some issues stopping drives since last update... Will write up once I RCA.

I noticed disabling smart, apply, enable, apply helped ! Some kind of GUI to config drift.

Troubleshooting still. seems 3 stopping from 6 now, but 3 running, trying to work out culprit/process.