As I'm having the same problems many do with trying to keep ZFS-formatted drives spun down (a RAIDZ in my case), I was wondering if a base Unraid installation with no additions (plugins, dockers, etc.) has been verified to be able to achieve that, at all. And, if it has, what are the required settings.

(If the Dashboard, alone, is prone to waking up the drives to do its reporting, it would need some kind of adjustment to limit that)

You don't need any other setting other than enable spin down, and as long as nothing is using the pools, they will spin sown normally:

The ZFS Master plugin is known to spin-up all zfs disks due to it refreshing the zfs snapshots. I don't know if you're using that plugin but if you are it has a setting you can disable to prevent this.

18 minutes ago, MowMdown said:

The ZFS Master plugin is known to spin-up all zfs disks due to it refreshing the zfs snapshots. I don't know if you're using that plugin but if you are it has a setting you can disable to prevent this.

I've tried setting it so that refreshing its data requires manual action, to no avail. I'll try uninstalling it.

It might not be the culprit, though: there are also the Dynamix System Temperature and Dynamix Auto Fan Control plugins: I'm happening to need them, as my motherboard's BIOS doesn't give me any means to regulate fan speeds based on HDD temperatures, and we are in the middle of a heatwave. They might be the ones waking up the drives, every time they check their temps. I guess I could manipulate their settings so that they exclude all the concerned drives while having a floor value high enough to keep them cool while spun up.

Easiest way to determine if it's a plugin is to boot into safe mode, and spin your disks down.

You really should post your diagnostics.zip

Edited June 30, 20251 yr by MowMdown

On 6/30/2025 at 7:49 PM, MowMdown said:

Easiest way to determine if it's a plugin is to boot into safe mode, and spin your disks down.

You really should post your diagnostics.zip

Thanks! Safe mode worked 🙂. I'll have to uninstall the most suspect plugins and reinstall and try them one by one.

My guess is the fan control one is the culprit, as it has to interrogate the drives for their temperatures. If the Dashboard can't show them already while spun down, that suggests getting the info will reactivate them. The problem is that I can't rely on the BIOS's fan curves (too old a board, "what's a fan curve?" 😒) to keep the HDDs decent. We'll see.

In the end I went that route: ZFS Master set to manual refresh, and having Dynamix Auto Fan Control to exclude all the concerned drives from reading their temperatures, while setting the minimum PWM values to ones that can keep them decent while they are active (max rpm, these days 🫠). I need to do that because this old mainboard's BIOS is too limited and won't let me set a constant value: it varies it in real time based on a mix of CPU and chipset temperature reads.

Edited July 4, 20251 yr by MetricTonto