On my system, I had set HDD Standby to 30 minutes. Based on my observations with version 25.10.0 during the night (without any read/write activity), the disks ARE spinning down after 30 minutes, but then they spin up after another 60 minutes. So I suspect the interval for reading the temperature is 90 minutes. Of course, I want my drives to stay in standby mode as long as possible. I have now reverted back to version 25.04.2.1, and hope the bug will be fixed soon (it was reported Oct 4, 2025).
That makes a lot of sense. Seems like fixing this from userspace is quite hard though as with a 60m spindown timer the temperature readings would need to be done very infrequently.
So either the drivetemp module needs to be fixed so it only actively reads the temperature when the disk is being recently accessed or spun down (quite a complication), or TrueNAS needs to disable temperature monitoring for disks that are set to spun down, or at least add an option to do so.
You could use the spindown script from the ngandrass github to allow spindown with the temperature lookups as it uses iostat to check for diskacivity instead.
However this currently doesn’t work as the temperature checks through smartctl instantly wake the drives back up, as it is no longer ignoring drives in standby since 25.10.
