# Config advice for a NAS
**URL:** https://discourse.nixos.org/t/config-advice-for-a-nas/80655
**Category:** Help
**Created:** [October 20, 2026, 8:26pm UTC](https://discourse.nixos.org/t/config-advice-for-a-nas/80655 "2026-10-20T20:26:34Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@PenguinRising](https://discourse.nixos.org/u/PenguinRising)
#### Post date: [October 20, 2026, 8:26pm UTC](https://discourse.nixos.org/t/config-advice-for-a-nas/80655/1 "2026-10-20T20:26:34Z")
I want to convert a backup system to serve as a NixOS NAS experiment. Since a NAS spends most of its time idling I am trying to figure out how to maximize the power-saving features. I am also figuring out the best way to have convenient monitoring.
The issue with power-saving is that most documentation which can be found is geared towards laptops. Obviously not that much of an issue, I could just ignore the battery parts. But I’m hoping there is something more targeted.
The obvious one is the CPU governor. It’s a few generations old Ryzen so the kernel driver is the EPP one apparently. This seems to bring its own challenges. The only clear instructions I can find on that is to use the `auto-epp` package which can then be set to `power` or `balanced-power`. There do not seem to be any instructions on how to set it statically without `auto-epp`.
The governor is another thing, the EPP driver only supports `powersave` and `performance`, so powersave it is.
What else can I do? Put USB and PCIe to sleep? What is already on by default and what should be declared in the config?
As far as monitoring goes, I would have `hddtemp`, `smartd` and figure out with `sensors-detect` what to do there (do I need to switch the `k10` driver to the `zenpower` driver?). `fancontrol` is probably also a good bet.
Any other tips? I see flakes here and there but they are focused mainly on the filesystems and prometheus/grafana, not the supporting stuff.
Thanks!
---
### Author:  [@colorfulcms](https://discourse.nixos.org/u/colorfulcms)
#### Post date: [October 25, 2026, 5:23pm UTC](https://discourse.nixos.org/t/config-advice-for-a-nas/80655/2 "2026-10-25T17:23:10Z")
For a mostly idle NAS, setting powerManagement.cpuFreqGovernor = “powersave” covers the governor, and powerManagement.powertop.enable = true applies powertop auto-tune (USB/PCIe runtime PM) at boot. If you want drives to spin down, check hdparm -S in a udev rule or services.udev.extraRules, but test it since some disks dislike frequent spin-ups. For monitoring, services.smartd.enable = true with sensible notifications is usually enough, and lm\_sensors plus hddtemp covers temperatures.
---
### Author:  [@PenguinRising](https://discourse.nixos.org/u/PenguinRising)
#### Post date: [October 29, 2026, 9:27pm UTC](https://discourse.nixos.org/t/config-advice-for-a-nas/80655/3 "2026-10-29T21:27:19Z")
Thanks for the tips. I ended up with this (relevant parts only):
```auto
hardware = {
# fancontrol = {
# enable = true;
# config = "";
# };
i2c.enable = true;
sensor.hddtemp = {
enable = true;
drives = [
# NVMe NOT SUPPORTED BY HDDTEMP
"/dev/disk/by-id/SSD"
];
# extraArgs = [];
};
usbStorage.manageShutdown = true;
};
services.auto-epp = {
enable = true;
settings.Settings = {
epp_state_for_AC = "balance_power";
};
};
powerManagement = {
enable = true;
cpuFreqGovernor = "powersave";
powertop.enable = true;
};
environment = {
systemPackages = with pkgs; [
powertop
lm_sensors
hddtemp
cpufrequtils
smartmontools
];
};
services = {
smartd = {
enable = true;
};
};
```
From what I read the fans are best controlled by the BIOS/system itself rather than software. I might make a derivation to enable the sensors overview for Cockpit as it’s not in nixpkgs. I looked into Prometheus/Grafana but that’s a bit much for my taste. And smartd still has to be configured, once I figure out how to make it actually notify me.
As for the spin-down, I’m on the fence about that. From what I know not a single platter-drive likes parking and spooling, so if I do end up using a single HDD as the first drive to process the worst of the writes I will probably keep it running. I honestly don’t know what the lifespan of an SSD is when downloading all those Linux distributions all the time.
It’s still not entirely functional, powertop won’t show CPU data for example, but it works. Still debating if I should put step-ca on it as well, to provide certificates for the dashboards internally. But I suppose the core is done.
Just seems too easy, like I’m missing something…
---
### Author:  [@MagicRB](https://discourse.nixos.org/u/MagicRB)
#### Post date: [October 30, 2026, 8:43am UTC](https://discourse.nixos.org/t/config-advice-for-a-nas/80655/4 "2026-10-30T08:43:48Z")
Ive yet to give this a proper read, but i saw spin down mentioned and alarm bells went off. Do NOT enable spin down under any circumstances. To make your drive last, it needs to spin at a mostly constant velocity (thats up to the firmware) and you should never move it while ite spinning.
---
### Author:  [@MagicRB](https://discourse.nixos.org/u/MagicRB)
#### Post date: [October 30, 2026, 8:49am UTC](https://discourse.nixos.org/t/config-advice-for-a-nas/80655/5 "2026-10-30T08:49:48Z")
Ok, so reading properly now, i dont have much to comment on power saving measures. Ive yet to do any tuning myself tbh. I will point out that I am not 100% sure switching governors actually gives any meaningful benefit on modern systems.