(⚡️<5W idle) The Milliwatt Miser: Odroid H3 Fanless SSD-Only NAS. a.k.a my tiny, humble, power efficient Unraid server.

// Disclaimer: As you may see, yes, I have used an LLM to help compose this post (10+ prompts), since I'm not a native English speaker. However, at least 80% of the text is my own, with some small parts having improved grammar. I spent a lot of time writing everything. I would never come up with such a clean structure.

My Unraid server is built for extreme efficiency—minimal power, zero noise, and maximum reliability.

Hardware

• Board: Odroid H3 (Intel N5105, turbo disabled)

• Memory: 16GB DDR4 Crucial 3200 (max. 64GB: 2x32GB)

• Storage:

  • Cache: 2TB Samsung 980 Pro NVMe

  • Pool: 2× 4TB Samsung 860 EVO SATA SSDs

  • Boot: 16GB Transcend JetFlash 180I (industrial SLC, ECC)

• Cooling: Fanless by design, with an 8cm Noctua safety fan (auto on at 60 ℃, off under 55 ℃)

Docker Services

• Core: Immich + Immich-Machine-Learning, Beszel + Beszel-Agent

• Everyday tools: FreshRSS, Portainer, Dashy (favorite dashboard), Jellyfin, Node-RED, Nextcloud, Mattermost, Vaultwarden, OpenVSCode Server

• Utilities & apps: Baby Buddy, Cup, Grafana, Prometheus, Docmost, Excalidraw, n8n, Syncthing, Gotify, metube, Nexterm, ESPHome, it-tools, OmniTools, ...

• Energy optimization: Many containers run only on demand and auto-stop when idle to reduce power and heat.

Power Efficiency

• Unraid 6.12.10 → 3.5–4.5 W idle (AC side, measured with Shelly 1PM) - see details later

• Unraid 7.1.4 → ~4 Wh average (DC side, measured with Riden RD6012P)

• see my older measurements:

  • https://forums.unraid.net/topic/11386-whats-your-power-consumption/#comment-1371090

  • https://forums.unraid.net/topic/98070-reduce-power-consumption-with-powertop/page/28/#comment-1363492

How I Achieved It

• Tuned with powertop --auto-tune

• Enabled ASPM for all PCIe devices (custom bash script)

• Careful SSD choice—Samsung 980 Pro (I found “Pro” models excel at low idle draw under ASPM L1)

• Learned, tested, and refined through Unraid forum tips, experiments, and SSD reviews.

• Thanks a lot to user @mgutt for sharing his knowledge about lowering power consumption in general.

Interesting Notes

• Serves my family as a backup hub, mainly for photos, and helps us track our newborn with Baby Buddy

• Runs mostly on solar-charged LiFePO₄ battery, switching to mains only when SoC drops below 25%

• Powered via Mean Well DRDN20-12 redundant PSU (dual inputs: battery + mains, one output to Odroid)

• Remote access secured with Tailscale

• Silent in daily use, with Noctua safeguard cooling for heavy workloads

• A minimalistic approach to storage: less data, less worry. I don't need to store everything, only the data that I cannot download from the internet.

Future Plans/Upgrade
I may consider an Odroid H4 for IB-ECC RAM support, but the Odroid H3 is more than powerful for me and has proven rock-solid reliable.

Most probably my upgrade will be just swap SSDs for bigger and add one more m.2 SSD for cache - for redundancy and better reliability.

Currently, I'm working on another very similar node that will be located in my brother-in-law's house, where some important data will be synchronized and backed up. It will be 100% solar-powered.

Final words

This setup keeps our family data safe while sipping less power than a phone charger.

It is sometimes even less power hungry than my Raspberry Pi 5 with 1x SATA SSD via USB. Silent, cool, and efficient—the true definition of a Milliwatt Miser.

I don't need expensive servers that draw over 100 watts and are noisy. I've been using Raspberry Pi for years, and the Pi 4 and Pi 5 are very capable, no problems with running 20+ self-hosted Docker apps. For me, the upgrade to the Odroid H3 was significant.

I'm amazed by the power efficiency of the x86 CPU; Intel did a good job there.

---

NOTE:

I apologize for the mess and cables around it in the photos. This server is hidden in my small rack. I just took it out on my table today for a photo and for some minor polishing and care during the upgrade to 7.1.4.

Photos/screenshots:

ℹ If you would like to see specific details, please ask, and I will provide more photos upon request.

I just took it out on my table today: Odroid H3 above, RD6012P below:

• Odroid H3 is in a random, unobtrusive metal case. Both SATA SSDs and the M.2 SSD (with large copper heatsink) have direct contact with the metal case for better heat dissipation.

⚡️ Power measurements - older:

• from AC side using Shelly 1 PM and Node-RED

• I was on 6.12.10 at that time and I had 2x USB flash drives (one for dummy array)

• I have created these graphs via Node-RED using REST API of Shelly 1 PM:

  • 

⚡️ Power measurements - latest:

• Using Riden RD6012P power supply (for me it is expensive "pro" laboratory power supply - it was an awesome gift from my wife ❤️)

• there are running my non-stop docker apps: Immich, Portainer, Dashy, Beszel

• +90% in C10

• here is 3,7MB GIF from 20s video capturing real-time idle power consumption from RD6012P:

-

video:

• when a bit less containers are running (it hits 2,63 Watts only!)

Please, do not compare both power consumption measurements. There are different UNRAID versions, different measurement tools (AC vs DC measurements), different HW configurations (USB devices).

⚡️If you want to see even smaller power consumption, check out my post about the Odroid H4 with only one M.2 SSD: https://forums.unraid.net/topic/167669-odroid-h4-intel-n97-2x25gbit-4x-sata-1x-m2-ddr5-max-48gb-with-ecc/#findComment-1567671 (⚡1,8 ~ 2,0 W measured at the DC side with a Riden RK6006)

Battery rack (sorry, I have no photo of the rack with my unraid server and cable mess from router and switches)

Fun fact - it's 90° rotated. Inside is one battery and Victron SmartSolar MPPT controller:

Here is my power scheme. I planned to use a 24V system, but I'm currently using a 12V system with one battery (Pylontech 100Ah 12,8V 1,2kWh), and it's great. I have no need to switch to a 24V system, as it's currently not possible with the one solar panel I have (120Wp).

r

CPU temps from Grafana:

• room temperatures are here 26~28℃ (hot summer here)

ascii diagram of my Odroid H3 unraid with 3x SSD (best to view on desktop)

 

 Unraid NAS                                (12V / 4Wh)
┌─────────────────────────────────────────────────────┐
│                     Odroid H3                       │
│                                                     │
│  Intel N5105                          Unraid 6.12.6 │
│  1x 16GB DDR4                                       │
│                                                     │
│                 2.5G  2.5G                          │
│     SATA SATA   LAN   LAN#2               USB2  USB2│
│M.2   #1   #2     #1   unused               #1    #2 │
└─┬────┬────┬──────┬──────────────────────────┬─────┬─┘
  │    │    │      │                          │     │
  │    │    │      └──► switch 2.5G           └──┐  │
  │    │    │                                    │  │
  │    │    │                                    │  │
  │    │    │              pool RAID1 (btrfs)    │  │
  │    │    │  (SSD)   ┌─────────────────────┐   │  │
  │    │    └─────────►│ Samsung 860 EVO 4TB │   │  │
  │    │       (SSD)   │                     │   │  │
  │    └──────────────►│ Samsung 860 EVO 4TB │   │  │
  │                    └─────────────────────┘   │  │
  │                                              │  │
  │                        pool "Cache" (xfs)    │  │
  │            (SSD)   ┌─────────────────────┐   │  │
  └───────────────────►│ Samsung 980 Pro 2TB │   │  │
                       └─────────────────────┘   │  │
                                                 │  │
                                                 │  │
     (boot) 16GB Transcend JetFlash 180I   ◄─────┘  │
      industrial-grade flash with ECC, SLC mode     │
                                                    │
                                                    │
     (dummy) 64GB USB2 ADATA Flash Drive   ◄────────┘
      array  for storing backups of bootUSB 
       - NOW UNUSED !!! (since unraid v7)

Terminal:

• showing ASPM status for all PCI devices, CPU temps and neofetch output:

Fun fact: I'm running old version of Immich.

I upgrade it once per 3~6 months. I'm doing it 2 years and so far no problems.

Edited August 19, 2025Aug 19 by bagican

As for using UPS for such low-power devices like routers, Raspberry Pi, … I personally don’t like it, it’s very ineffective.
Why? Such devices work on DC voltage (e.g. 12V).

Standard UPS has 12V battery (DC) and DC to AC converter to produce ~230V AC and mentioned devices need conversion back to DC (AC to DC adapter to 12V or 5V). There are a lot of losses and unnecessary conversions.

                  ┌───────────────────────────────┐
                  │             UPS               │                                    12V/5V DC
┌─────────┐       │                               ├──────┐       ┌─────────┐           small devices:
│         │       │                               │ AC   │       │  AC/DC  │
│AC ~230V ├──────►│    ┌──────────────────────┐   │~230V ├──────►│ adapter ├───┐
│         │       │    │    AC/DC, DC/AC,     │   ├──────┘       └─────────┘   │
└─────────┘       │    │                      │   │                            │ 12V
                  │    │charging circuits,... │   │                            └───────► Router
                  │    └────────▲──┬──────────┘   ├──────┐       ┌─────────┐
                  │             │  │              │ AC   │       │  AC/DC  │     12V
                  │             │  │              │~230V ├──────►│ adapter ├───────────► Switch, Odroid H3
                  │             │  │              ├──────┘       └─────────┘
                  │   ┌─────────┴──▼────────┐     │                              5V
                  │   │                     │     │                            ┌───────► Raspberry Pi
                  │   │                     │     ├──────┐       ┌─────────┐   │
                  │   │      12V battery    │     │ AC   │       │  AC/DC  │   │
                  │   │                     │     │~230V ├──────►│ adapter ├───┘
                  │   └─────────────────────┘     ├──────┘       └─────────┘
                  │                               │
                  └───────────────────────────────┘

but there are DC only UPS devices:

                  ┌──────────────────┐
                  │      DC UPS      │                           12V/5V DC
┌─────────┐       │ (MeanWell        │                           small devices:
│         │       │   DRC-100A or    │
│AC ~230V ├──────►│   AD-155A or     ├────────────────────┐
│ or sun  │       │   PSC-100A)      │                    │
└─────────┘       │ or Victron MPPT  ├─────────────┐      │12V
                  └───────┬─▲────────┘             │      ├──────► Router
                          │ │                      │      │
                          │ │                      │      │12V
                          │ │                      │      └──────► Switch, Odroid H3
                          │ │                 ┌────┴────┐
                  ┌───────▼─┴───────────┐     │ DC/DC   │  5V
                  │                     │     │converter├────────► Raspberry Pi
                  │                     │     └─────────┘
                  │      12V battery    │
                  │                     │
                  └─────────────────────┘

I personally throwed some power adapters (AC/DC converters with 5V and 12V output) and replaced it with one strong 12V power supply with DC UPS.

If you need monitoring capabilities and data about battery levels, charging,… you can change DC UPS (MeanWell) to some solar controller (like Victron SmartSolar or EPever, but that’s a bit pricier, however, they do provide an API so you can get data and graphs from them).).
And solar controllers have usually higher efficiency.

Power Supply Redundancy

It’s useful for powering critical devices.
It’s like RAID.
When one power supply dies, you have second power supply connected to ~25 Eur device called DRDN-20-12 called Redundancy Module

• more info - how it works, how to connect it: DRDN20/40 & ERDN20/40 series 20A/40A Power Supply Redundancy Module -MEAN WELL Switching Power Supply Manufacturer

   ┌─────────┐    ┌─────────┐
   │  AC/DC  │    │         │
   │ power   │    │ power   │
   │  supply │    │  supply │
   │    #1   │    │    #2   │
   └────┬────┘    └────┬────┘
        │              │
        │12V           │12V
        └─────┐  ┌─────┘
              │  │
        ┌─────▼──▼─────┐
        │   Redundant  │
        │     unit     │
        │              │
        │ (DRDN-20-12) │
        └──────┬───────┘
               │
               │12V
               ▼
 ┌──────────12V_devices────────────┐
 │                                 │
 │ Router, switch, unraid server,… │
 │                                 │
 │   12V -> 5V ---> Raspberry Pi   │
 └─────────────────────────────────┘

BTW: I'm also experimenting with supercapacitors (you can think of them as power banks with very small capacity), and they can keep my server powered for about 60 seconds (depending on the load). With custom real-time monitoring and automation, they can serve as an additional layer of power reliability improvement or for specific situations. I can write more about it if there will be an interest.

Edited August 17, 2025Aug 17 by bagican

Thank you!