My two internal HDDs (Seagate) immediately wake up after they go to sleep.
hdparm -y /dev/sd? doesn't work and even if I set a spindown time they will just stop and immediately turn on again.
I'm on Fedora (BTRFS).
Not sure if it matters but earlier it worked on Arch. I remember that I had to change the spindown time from 15 minutes down to 10 minutes because of a game. Then I used the computer as a server and the HDDs spun up after approximately a minute spindown time.
There is no smartctl installed. What is the problem? I don't think that a reading or writing process triggers the HDDs because they do go to sleep if I set spindown using hdparm.
There's only a nextcloud instance running (and newly a satisfactory instance). The cron jobs of nextcloud aren't the problem because they only launch all five minutes and if I remember correctly wait until they're 3 (so 3 threads,
3 * 5 = 15).
iostat I determined if there's any disk activity and it turned out that as soon as the
hdparm -y command is executed there's something written to the disks (previous kb written:
hdparm -y: 114293529). The read did not increase.
It looks like the HDDs now go to sleep if
hdparm -S equals one minute but I am not sure for how long. I think about five minutes, depending on what's happening.