I'm using CachyOS with a Linux kernel, and I have a single Toshiba 3TB HDD for storage alongside my SSDs. I want this HDD to go into standby mode since it's mostly not in use, but it just keeps spinning. I tried setting the standby timer with `hdparm -S 6 /dev/sda1`, which applied the setting but didn't help. Using `hdparm -y /dev/sda1` made it spin down for a second but doesn't sustain it. It spins down fine when I unmount the HDD, but I don't want to keep unmounting it every time I'm not actively using it. What should I do to make it spin down automatically?
3 Answers
If you're not actively using it, why not just unmount it? Having it mounted at boot can slow down your startup time, and it sounds like leaving it unmounted fits your usage. Tools like Dolphin allow you to mount and unmount it easily when needed.
Consider using the `-B` option along with `-S`. This setting adjusts the Advanced Power Management feature of your drive. A lower value enables more aggressive power management and allows for spin-down; a value of 1 provides maximum power savings but may affect performance. You might want to play around with these settings to find what works best for you.
Not all HDDs support sleep timers, but the `hdparm -y` command should normally work. First, check if your HDD is being accessed constantly by using the command `grep sda1 < /proc/diskstats`. Wait a bit and see if there’s ongoing activity affecting it.
Thanks for the tip! Is there any way to determine if a specific HDD supports a sleep timer before buying it?

I had issues with terminal emulators when trying to unmount. Some programs seem to struggle with that setup.