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Comment by heywire | Hacker News Reader

Another option, if your needs are relatively modest, is to choose a low power mini PC. The one I chose idles at around 5W under Linux before any tweaking. It is based on the Intel N5105. I have a few 2.5” external HDDs attached for backup which are configured to sleep after a short time.

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I'm curious if you have measured power at the well (e.g. smart plug with energy metering or Kill-a-watt.) I just set up a test server with a J1900 (10W TDP.) With 8GB RAM and running from an SSD it uses 25W. Add 4 7200RPM HDDs and it's up to 65W idling.

I have another test server based on a Raspberry Pi 4B. The Pi boots from SD card and uses about 5W. Add 2 drives in a USB drive bay and power for the setup is now up to 25W.

This was measured with an old school Kill-a-Watt. When idle, the HDDs spin down. Keep in mind these are 2.5” likely 5400rpm or less (WD Passport 2TB).

UPS’ also have this feature and it’s interesting to see the idle vs load wattage.

I like the idea of making compute, storage into appliances if possible locally.

It’s best to use ssds in the machines.

If you want spinning drives put them in a dedicated nas for storage.

> I just set up a test server with a J1900 (10W TDP.) With 8GB RAM and running from an SSD it uses 25W.

Did you use a regular desktop power supply? PC power supplies can consume 10-15W or more at idle. To build a low power system you need to find a good low power, high efficiency power supply.

Does anyone know a good supplier for such supplies?

For 10 years my home server used a Corsair VS350; it was fantastic, and very efficient at low power draw. Recently the fan failed. The PSU seems discontinued. The _fan_ seems discontinued. I'm going to try replacing the fan but I don't know much about electronics. As a temporary measure, I got a regular "gaming PC" PSU and it has 10% more power draw, it's not efficient at all.

I've been looking for a replacement PSU, and I can only really find very high power ones - minimum about 550W - for reasonable prices. While you can run a low wattage PC on such PSUs, none of them make very much in the way of efficiency promises; only the highest certification, 80 Plus Titanium, makes efficiency promises for 10% load, e.g. it'll be 90% efficient for a 55W load on a 550W supply. Lower certifications only promise to be e.g. 80% efficient for a 110W load on a 550W supply, and make no promises at all about a 55W or 30W load.

So, how does one buy a good low power, high efficiency PSU, without it costing a fortune?

> I'm going to try replacing the fan but I don't know much about electronics.

Just in case: opening PSUs is dangerous without precautions. The capacitors may retain enough charge to kill.

Besides the immediate risk to yourself, a PSU can also pose a fire hazard during operation, e.g. if improperly cooled.

2.5" hard disks actually use way less power than the 3.5" drives, but if you spin down the bigger drives they get down to about 1watt.

My server at home I actually use a 2.5" drive for the torrent scratch disk since I don't really need speed there I just need something that is always spun up with a moderate amount of space that doesn't use much power.

Running powertop --auto-tune and TLP makes a lot of difference on my server (60->30W). You can further tune CPU, disks and GPU to preserve energy. I suggest starting with a laptop or a phone (~postmarketos)instea d,as those are already tuned for low-energy modes, and you won't have, say, a BIOS preventing PCI devices from sleeping (looks at server).

Another option is to use a smartphone with damaged screen, USB Ethernet card and an external USB drive.

This was always attractive to me, how are you running a linux host on the phone or are you just using native android hosted services?

I use a custom firmware with Termux. It's enough for me.

https://medium.com/junior-dev/how-to-re-purpose-your-old-and...

That looks good enough for me, thanks!

Don't forget to turn on option "Don't turn screen off when charging". Use a less powerful charger to power the smartphone. 5 Watt charger is enough. 2.5 Watt may work too.

I think you'll be disappointed by the kernel support, especially if you want to run docker containers or anything like that.

Indeed, running docker on android requires a custom kernel: https://gist.github.com/FreddieOliveira/efe850df7ff3951cb62d...

The pixel 6 and 7 have full KVM capabilities tho: https://www.patreon.com/posts/74333551

The pixel 6 and 7 options are awesome

You could also use postmarketos, mobian, etc. Have a look at the pmOS wiki for device support, most support USB OTG, and usually you don't need GPU acceleration nor screen/audio/cameras, which are usual pain points.

Low powered pcs are the way to go for self hosting.

Lots of great options that sip power at idle (most of the time)

Desktop grade cpus can be found that max at 35W.

The power per watt of sa

Completing the sentence above

Cpu-Power point per watt is what you're after.

And then, electricty cost per watt-point.

8th gen intel and above cpus are quite perfect for this, they often have hyperthreading and vPRO built into an enterprise/military grade box for hundreds and have near perfect linux support out of the box, whether it's Lenovo, HP, Dell, etc.

I've just bought a Pi for some always on stuff (like Home Assistant). I wanted to buy a mini-PC but I found it really hard to identify which ones would have low idle power. Did you find a good reference for this?

A lot of times I want to build something on my homeserver and N5105 ain’t gonna cut it. I don’t build every day or every hour but if I want to I would have to turn it on and off every time.

Honestly, this is the right answer. I have a HP ProDesk 300 G3 mini (the mini version of the server the OP is using) running home assistant, syncthing, a bunch of other random 24x7 stuff, and the "server", router, and PoE switch powering two Wifi APs is drawing a grand total of 9 watts*. It just doesn't seem worth the effort to try and make this more efficient.

* According to the UPS.

I feel like there's a lot of room in the market for a chip that sips power but has a billion PCIE lanes and RAM.

Does such a system exist?

PCIe switch chips can be used to multiplex many devices on to a few lanes already, today.

There isn’t much market demand for an extremely low power chip with excessive PCIe IO and a ton of RAM because most applications with high RAM and IO requirements are going to be very power intensive.

It’s already possible to build an Intel system with plenty of RAM and IO where the CPU doesn’t take much power.

For building a high capacity NAS you don’t need the throughput of PCIe for all of your drives. Cheap SATA SSDs can easily saturate your network link when used in parallel.

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