Saving Energy: Home Server That Automatically Suspends to RAM and Wakes Up Again

Interesting! I believe all the new Mac products also work like this. While sleeping a Mac will still stay on WiFi if it’s on a power adapter and the sleeping M1/M2 Macs stay on WiFi even while on battery. They also still respond to some mDNS traffic. When I try to access certain services on a sleeping Mac, like SSH, it’ll immediately wake up. Even port scanning with `nmap -p 22 <ip>` will cause a wake up. That sounds like the wake on “directed packet” thing? In practice I think this mostly obviates the need for a Bonjour Sleep Proxy.

Also, fun tip: You can easily check if a Mac on the network is sleeping or not based on its ping response TTL. While awake it uses a TTL of 64 but while sleeping it uses a TTL of 32. You can use this little signal to roughly keep a log of when the Macs on your network are awake vs sleeping. (Not too much of an actual privacy concern I think)

And you can have most of it with a banal sleeping/waking up by the schedule. Regular Joe sleeps at night and works at day.

EDIT: btw, this solves "if Time Machine starts a backup" completely.

About 41 euro cents per day->57€/140

3360 is the number of hours in 140 days.

Ok, the implementation wasn’t very fantastic cost wise. However I still think this could be a big area of improvement. How can we reduce energy usage of servers?

There’s a lot of work with ARM lately, I’m curious if that could be used in server workloads like this.

You can very quickly run up against resource constraints with a raspberry pi.

Pi doesn't work that great, power consumption is still several watts, too much for batteries to be cheap and compact if you want a day or two of backup, plus self hosting in general is very much enthusiasts only.

Android does what Docker does while remaining very low power, because it gives you one standard API level, rather than some minimal syscalls and you have to bring all your own libraries right in the container.

As I see it there's a few missing features, and they need to be solved anyway to make self hosting less painful in general, right now I don't see many good ways to do it at all unless you like stuff that unpredictabily needs maintenance.

Play store needs to be split into provider and interface APIs, so you can add your own repos and still have it work with existing tools.

Remote management needs to be a thing for sure, installing apps is the hard part of that. WearOS does it amazingly, just connected to BT and the host play store does it, but you'd need the split app store to make that work well with open source third party repos.

Automatic updates would be solved by that, just deploy your app on a repo, and update via the play store or your interface app of choice.

Finally you'd have to solve the biggest problem with ANY self hosting as far as I'm concerned, how to handle certs and domains with zero manual IT work(Has to be truly zero, no chance it needs maintenance while you're on vacation).

I've been saying this for a while, we need pubkey-based domains like .onion URLs, but without the onion routing, so there's no dependence on a CA or anything that might be hard to do in a fully automated "Scan the QR and connect" context.

Or, more likely, Google gives you a service.yoursubdomain.google when you buy Google One, and routes stuff ngrok style for you, with lots of spying, because P2P hasn't been their thing so far. Perhaps one of the forks could do it though.

Without eliminating domains and certs, I'll continue mostly ignoring self hosting, I don't want any chance it goes wrong while I'm too busy to fix it, since there's no dedicated support staff, just me.

It would also solve the other half of remote admin, apps could just declare a web interface for admin that you access if you have the secret URL.

Then you'd need some systemd alternative to manage processes. You'd have to be able to say "Start this on boot, restart it on failure, and never clear it out of RAM".

On the hardware side, phones are already close to perfect. Keep the screen and NFC and Bluetooth, for QR based connections and the like, keep the battery as a UPS, but add more USB ports, Thread/Matter, and ditch or downgrade the cameras.

The filesystem probably needs to support snapshots, and Android should get a Full Backup and Restore Provider API to make it easier to back up everything, just the home folder, just one app, just the settings, just the data, etc, to your chosen provider, maybe even with hooks for apps to respond to import and export, so that the state of your app is totally portable and needs only a few clicks to restore from auto backup.

Finally, we need a cpanel-like VPS management tool to migrate your stuff to cloud hosted if you want, that can take backup files, and show you what's on the remote device's virtual screen(Again, so QR stuff works) or at least what's being displayed via some "Admin screen API" if you don't want to drag the full graphics API into it(But keeping graphics all the time seems like a good plan for standardization, and for kiosk type stuff).

And then finally, you'd probably want a some of the features from a normal-ish Linux userland, or as close as you could get, to make porting existing stuff easier, but even without that, I'd say the porting would be worth it.

Battery will be a spicy pillow in a year or two of 24/7 usage. It’s accelerating the wear to considerably more than a heavy user or shop demo model

Need a phone that works with the battery removed or a fake battery

> The power saving is not because of Android it is because of the ARM arch being used under the hood.

[citation needed]

Based on my understanding, the underlying OS has way more to do with power usage than the instruction set, and AFAIK Android has tons of optimizations specifically geared towards reducing battery consumption (and therefore power usage) on mobile devices.

With that said, it's true that, in practice, the power floor seems to be lower for ARM devices than, say, x86, but I'd wager that this has far more to do with target market than with ARM's instruction set. Low power x86 boards do (did?) exist.

I'm no Java enthusiast but this screams for source.

I'v always thought it is how iOS manages threads vs in a way Android cannot. But all that info is from more than decade ago, so things may have changed. Can anyone chime in to explain?

To this day iOS feels snappier, perhaps lower latency input/output or something. Am saying as someone who uses and prefers Android and currently using Samsung Galaxy S10 phone (flagship phone line)

Android has the NDK now, it can run native code with only tiny headers of java to launch it, plus ART compiles the Java anyway as I understand it.

Regular Linux could be tweaked, but I think it would be way easier to start on Android and add all the missing stuff you want for a server, than to start on Linux.

Regular Linux still uses a bit more power, and they don't have any kind of container+sandbox that works quite as well, on account of the very tiny userland API that requires containerized things to bring all their own libraries, making them like 800MB a lot of the time, can't really run more than a few apps in 16GB of cheap slow flash like that.

Android doesn't run apps in a Java VM. At build time, the Java bytecode is translated to DEX bytecode, which is designed specifically for Android. Today, at install time, the Android runtime compiles DEX bytecode to native code. You're probably right about this being true in the early days, but not so much anymore.

I think the power usage difference between Android and plain Linux on the same hardware is mainly due to the way Android aggressively puts the CPU into sleep states and uses timers (etc) to wake it up as needed.

I accidently discovered earlier today that the Fairphone 3 works without it's (easily swappable) battery. So maybe other brands still build them like this.

Since we're talking about an Android phone for self hosting, if the phone is glued/the battery is soldered, after rooting it, the Advanced Charging Controller App* may be an option.

* https://f-droid.org/packages/mattecarra.accapp/

I have a synology nas and is unable to stop the spinning disks. A shame, every other thing in it is nice, but could have beter optimizations, as the disk are the most of its energy consumption.

I'm running it's older cousin - N36L with 4 Drives. The CPU in that one is Athlon II Neo N36L with 12W TDP, 3.5" spinning drives are 7-10W per drive. So 40W is very reasonable.

Op should just run more services on his server, but that probably won't be 43W at idle, when the box would actually be doing something ...

And it generally lowers longevity if disks are slept and woken up constantly.

I don't think it has improved much. No one has been benchmarking these metrics for desktop PCs for a decade or so, so they have gotten worse, if anything.

I have not yet found any LGA 1700 motherboard were the total idle power would be less than 25W, for example. I find that the power supply inefficiency by itself, even on standby , is usually already 2W -- larger than some of the alternatives discussed here. I have to go to Intel's soldered solutions to find <10W idle consumption (and even <2W). Forget about last decade's desktop AMDs either, they have very high idle power, with the exception of some APUs that may go down to 10W. They may also have custom solutions that idle at significantly less, though.

If you find something with thunderbolt, you can get an external controller in there via thunderbolt->pcie. But between that power draw, and the draw of the drives, you'll be bumping close enough to 40w that it'd be a wash.

I do this math myself every few months and ultimately, it seems for a large nas/server, 40-50W is about as low as you can idle.

Maybe a QNAP box? I think they're just PC's, so you can just wipe QNAP's OS and install whatever you want (unlike some other NAS vendors).

Europe energy prices :/ Here in Texas it cost maybe $5/month to run a 45 watt little server (pc)…

You're right, using a desktop CPU for a mediacenter is not a good idea.

Laptop CPUs are, however, really well optimised for very low consumption when idling and that's what you should be using for a mediacenter.

Also, IMHO, ASRock Deskmini would not be a good idea for a media center since it's using desktop CPUs. The idle power draw will not be as good as mini pc with a laptop CPU.

> I've found that most desktop PC-s have idle power usage around 35-50W.

My desktop server uses 50W at idle. ASRock Z390 motherboard, Pentium G5400, 32GB RAM, no GPU. There are 15HDDs, but 50W is with all of them spun down. It hits 120W will all disks spun up and CPU under load. I've come to the conclusion it's the motherboard, because the parts individually shouldn't draw that much power.

ATX even needs -12V, which was useful for RS232 at that point I guess.

Even on a fairly old one (my "home server laptop" is 8 years old) it's really close in terms of power usage. And the laptop is much faster than the Raspberry and usually comes with fast SSD storage built in.

Same here but with an XPS 13 model. Power usage from laptop chips is great for home servers. They're still really fast when needed compared to a Raspberry Pi, and typically come with 256gb or even 512 of built in fast SSD storage.

The battery in mine is old, but with the screen off it still lasts several hours as a sort of UPS.

I was doing it and it worked fine. But I'd just keep the served content on the disk. Of course not /var.

>Does Time Machine run on a schedule? Add a cron job (whatever the Mac equivalent is) to send a WoL ~1min beforehand?

I believe on x86 the BIOS supports setting a timer for self-wakeup. The OS can tell the BIOS "I'm going to sleep. Pull me out of sleep if the RTC passes this datetime."

Reverse proxy means that your pi now has to handle all the traffic for Plex and any other services. It could also make other things difficult like CIFS/whatever else you're hosting.

Depending on what Pi you're using, it's networking is over USB, and so is quite performance constrained.

Thinking of Icinga or other monitoring tools, they would trigger such a request everytime.

keepalived seems like a great idea.

I'm not sure how Plex clients would handle it, but putting an nginx server with the same certificates and just returning HTTP 429 (Too Fast) or 500's and a "Please try again in 1 minute" response, along with sending the magic packet would work great for most HTTP based things.

> For those who go, "but I need real power"

I think those usually also want real storage space, NVMe either can’t offer that, or it would make the build so expensive, electricity stops mattering. And in those cases, 4-12 24 TB HDDs will out-consume your other hardware anyway ;)

> The later hardware revisions (such as 1.5) of the Raspberry Pi 4B, even with 8GB of memory, can idle at ~1.33W on WiFi

How is this measured? I spent _years_ doing experiments on the Raspberry Pi 4B and was never able to get it to idle to anything less than 3ish W at the wall, albeit arguably this was not with the "1.5" hardware revision.

One day I bought an ASUS PN40, which has an x86 Intel N4000 CPU.... and on the first day, just after installing openSUSE, without even customizing _anything_, I measured _1.7 W_ power consumption at the wall. This is for a full x86 server, with GbE ethernet, 8GB of RAM and a 1TiB SATA SSD.

That server is still my one and only homeserver. It has my calendar, media files, talks to my Zigbee/BluetoothLE devices, and it does so at a fraction of the power used by the Raspberry Pi that TFA uses for waking up his homeserver.

> For those who go, "but I need real power"

There's also the flip side, which is "well since I already have real power..."

I.e., like many HNers, I own a powerful coding/gaming Linux desktop with plenty of HDD space, which gets regularly backed up to cold storage. It does however use a frankly obscene 90W when idling, due to the GPU, fans, and multiple hard drives and peripherals.

Building a separate, power-efficient home server would take a year or two to break even, even compared to running the workstation 24/7. But it's more like 3-5 years when you consider that it's going to run several hours most days anyway, and that it can be safely put to sleep at night. Plus of course it's more effort to manage two servers rather than one, so everything else being equal the single desktop is preferable.

Now if I can use some of the tricks described in this thread to turn it off when I'm not using it, and only temporarily wake it up when I need to stream or upload something, then using the desktop as a home server becomes kind of a no-brainer.

Of course, if you only use a laptop, then a low-wattage home server is a totally sensible complement.

A refurbished Fujitsu FUTRO S740 thin client, it has one SATA m.2 slot, and I replaced the Wi-Fi m.2 with an adapter for an extra NVMe. They are pretty big in Germany as small homeservers, because there are a lot of used ones around (I paid 44€ for the 8 GB version). There’s an overview [0] page for them, and a list of power measurements [1], both in German, though.

[0]: https://github.com/R3NE07/Futro-S740/blob/main/README.md

[1]: https://github.com/R3NE07/Futro-S740/blob/main/power_consump...

not necessarily, depends on the embodied emissions in the replacement gear. It is also surprisingly hard to get any information on those. I tried seeing if there were estimates of the kg co2 in a modern CPU chip but I found nada

eeeeeh probably putting the money into getting solar panel would be a better deal eco-wise

We know why we can't have cheap and efficiently delivered power in California: PG&E has no incentive to deliver such a product.

My solution is to run my servers and live life as I please (within some degree of reason), and not look at the power bill too often. In my experience, the monthly charges don't correspond with my actions attempting to reduce or increase consumption in specific categories (e.g. hottubs, servers).

With that said, I do flip off the lights when not in use :p

True, but the high prices mostly come from company greed. They were insanely high even before that.

If it sounds unbelievable, that's because it isn't remotely true. DDR5 is 13% more efficient than DDR4 and has 4 times the max die density. 256GB broken up into four 64GB sticks would use about 8 watts.

This person make insane claims about power all the time. They claim nothing will surpass old raspberry pis and intel atoms in efficiency, that nothing will surpass 1 gb networking due to power constraints (even though it all has existed for well over a decade) and even claim that certain video games won't be playable in the future from power constraints.

It is best not to think about it too hard.

ah so you're a new windows user

Windows in particular is notorious as of late for brutally draining the battery while Sleeping[1].

[1]: https://www.youtube.com/watch?v=OHKKcd3sx2c

Same. At least not on desktop machines.

I had a similar problem with identical monitors that I used something called displayplacer

https://github.com/jakehilborn/displayplacer

Later I chained the displays differently and moved the adapters around so it stopped being an issue.

I'm amazed at the regression in this on Linux in recent years. It's a complete coin toss whether sleep will work at all on my laptop, and what state it will be in when I open in again.

Agreed. I find Macos on a fresh installation and new hardware will work fine, but over time it seems to fall apart somehow. The last Mac I used (when I worked for $FORMER_EMPLOYER) would sleep fine but whenever I woke it up several hours later I had a 50% chance of it being completly flat (and the other 50% it would have varying levels of charge). It got to the point I got into the habit of plugging my Macbook anytime I needed to wake it up after several hours of sleep to ensure it actually would wake up properly. This was because occassionaly it would wake up for a few seconds and durin that time it'd trigger another suspension which would itself fail to work and power-off part way through the suspension requiring a fresh boot. Battery supposely fine etc and would usually go for several hours no issues while still powered on. YMMV of course but I've had better experience with Linux and Windows on my Lenovo ThinkPads--if it goes to sleep at a certain level of battery charge then it usually wakes up only a few percentage points below that after several hours. shrugs

I said desktop OS. :V

The mini is just what I thought of off the top of my head and I know it performs well.

I fixed my post to put the 6 digit I forgot in the Intel mini specs.

You bring up a good point. Some of those little NUC boxes are really low. And a modern Raspberry Pi (if you can find one) is too.

Lots of options.

I use a USB 3 harddisk for that. Even my 8 year old "home server laptop" has usb 3.2 support which is faster than the disks can do anyway.

Some laptops take more than 1 disk especially if they are old enough to have a dvd drive you can remove

My Laptop has a Sata connection inside. Also, USB3 is fast enough. And even an additional nas only consumes 10-20W.

Why do you need ECC memory for a home server? What's the use case?

And they're blaming Putin...

But I don't want to pay the spin up price all the time.