Disk spin-down: What program to use and best practice today?

[MrNice]

@karlmistelberger

Does reboot change behavior?

Mar 23 10:02:42 erlangen hd-idle[760]: spindown: sdb 
Mar 23 10:03:56 erlangen smartd[2757]: Device: /dev/sdb, type changed from 'scsi' to 'sat' 
Mar 23 10:03:56 erlangen smartd[2757]: Device: /dev/sdb [SAT], opened 
Mar 23 10:03:56 erlangen smartd[2757]: Device: /dev/sdb [SAT], WDC WD40EZRX-22SPEB0, S/N:WD-WCC4E2FYXSNV, WWN:5-0014ee-262d2e71e, FW:80.00A80, 4.00 TB 
Mar 23 10:03:56 erlangen smartd[2757]: Device: /dev/sdb [SAT], found in smartd database: Western Digital Green 
Mar 23 10:04:05 erlangen smartd[2757]: Device: /dev/sdb [SAT], is SMART capable. Adding to "monitor" list. 
Mar 23 10:04:05 erlangen smartd[2757]: Device: /dev/sdb [SAT], state read from /var/lib/smartmontools/smartd.WDC_WD40EZRX_22SPEB0-WD_WCC4E2FYXSNV.ata.state 
Mar 23 10:04:05 erlangen smartd[2757]: **Device: /dev/****sdb**** [SAT], 4 Currently unreadable (pending) sectors**
Mar 23 10:04:05 erlangen smartd[2757]: **Device: /dev/****sdb**** [SAT], 1 Offline uncorrectable sectors**
Mar 23 10:04:05 erlangen smartd[2757]: Device: /dev/sdb [SAT], state written to /var/lib/smartmontools/smartd.WDC_WD40EZRX_22SPEB0-WD_WCC4E2FYXSNV.ata.state 
Mar 23 10:04:12 erlangen hd-idle[760]: spinup: sdb 
Mar 23 10:04:15 erlangen smartd[2757]: **Device: /dev/****sdb**** [SAT], 4 Currently unreadable (pending) sectors**
Mar 23 10:04:15 erlangen smartd[2757]: **Device: /dev/****sdb**** [SAT], 1 Offline uncorrectable sectors**
Mar 23 10:04:25 erlangen smartd[2757]: **Device: /dev/****sdb**** [SAT], 4 Currently unreadable (pending) sectors**
Mar 23 10:04:25 erlangen smartd[2757]: **Device: /dev/****sdb**** [SAT], 1 Offline uncorrectable sectors**
Mar 23 10:04:35 erlangen smartd[2757]: **Device: /dev/****sdb**** [SAT], 4 Currently unreadable (pending) sectors**
Mar 23 10:04:35 erlangen smartd[2757]: **Device: /dev/****sdb**** [SAT], 1 Offline uncorrectable sectors**

I am not certain to understand everything in your test. Sorry for my ignorance.
Correct me If I am wrong;
In your above code, I see, the device spindown, smartd can’t access the device (this is expected), then the device spinup, smartd still can’t access the device (not expected). Why?
Did you check physically the HDD is in fact spinning? This is why I added hdparm, it reports the real HDD state.

Thank you for your time.