Hi @zeroZshadow and anyone forcing the disks to spindown without patching the middlewared files.
The smart check in TN, which in 25.10 cannot be configured anymore, triggers every 90 minutes, and may spin up the disks depending on the model and how it reacts to smart queries, both my Seagate models gets spun up by that.
If you are using ZFS dataset encryption, the disks will spin up every 24hours as the sync_db_keys job triggers a write to the pool.
If you are using 2.5 inch disks spinning up that frequently may be fine but if you are using high RPM 3.5 disks that may significantly reduce its lifetime.
Another problem @zeroZshadow , you said you are using 3 hours standby time.
TN uses hdparm, which has multiple issues with long timers and some hdd models.
My Seagate Exos for example only work with up to 90 minutes standby timer using hdparm… timers longer than that are simply ignored.
Need to use seachest tools for that to work properly.