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Comment by ChuckMcM | Hacker News Reader

The author is not wrong, there is a lot of old hardware out there that is still more than serviceable for many things. But the loaded cost (power, maintenance, space, etc) of running servers at "home" can be way more than the $10 a month for a droplet on Digital Ocean.

What I'm saying is that the math isn't as straight forward as it might appear.

That said, it is now pretty straight forward to build a 'nano-datacenter' consisting of an enclosure, thermo-electric cooling, rack, switch, UPS, a server providing NAS storage and a couple or 6 servers providing compute. Plug its PDU into the socket where your dryer used to plug in out in the garage.

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I have an old Thinkpad T23, it's about 15 years old. It can run Windows 7 (with aero off) perfectly well, and also stuff like Libre Office. Linux is not so good on it, due to having to play with the graphics drivers, which I've never really got working.

It all falls apart when you want to use the Web. A Thinkpad T23 with a Pentium3 CPU just cannot render Modern Websites at acceptable speeds.

Basically if it wasn't for heavy JavaScript websites, most people could still be using decade-old machines for their day jobs.

Indeed! I used to run various services on my older generation hardware, but I realised that I was spending more than $70 a month on electricity to do so!

It's much cheaper using a couple $5 VPSes for services. The only hardware left at home that is on 24/7 is my NAS, which is because 20TB of storage costs too much in the cloud.

Have you considered Google Suite? https://gsuite.google.com/

You'll need a domain name to associate (and handle email, etc), and while technically you need 5 users to have unlimited storage, at the moment it doesn't seem to be enforced and a single user does have it.

Currently I'm storing ~50TB for $10/month. At this price and having 100Mbps Internet connection, I only turn on the NAS for local backups.

That's great, but what happens when Google kills the offering or suspends your account for violating their TOS?

Don't be surprised when Google suddenly starts enforcing space limits and dumps your data.

If you can deal with IPv6, Vultr instances go for as low as US$2.50 -- or $3.50 with IPv4. It's insane.

I use an old HP laptop/netbook for my personal stuff at home. Running is private git repos, dnsmasq with ad-blocking host, and Syncthing to keep my files handy at all times. I force it into powersave mode using cpufreqd and throttle the CPU to the lowest step. I haven't put a power meter on it, but I can't imagine it's using a ton of wattage. If it fails, there are a few others in my office to take its place.

I love using old laptops for servers, built in UPS and everything.

I've been advised to remove and recycle the batteries due to safety concerns. Apparently when they are designed, they are not designed to be on 24/7. My laptop's batteries are toast, anyway, so it doesn't make a difference to me.

It's not so much that they can't be used 24/7, but that Li-Ion batteries really don't like staying at 100% charge (nor 0% either for that matter).

If you can configure your laptop to only charge the battery to ~80% or so, you'll extend the battery life significantly. The optimal range for long-term storage is ~40-60% charge.

Older ThinkPads have a driver to limit battery charge range:

http://www.thinkwiki.org/wiki/Tp_smapi

What are you using for adblocking? I was thinking about setting up pihole, but I already run bind at home for a private zone and I didnt want to deal with setting up forwarders. Are you integrating adblocking with bind by any chance?

Checkout - https://github.com/Trellmor/bind-adblock

Which incorporates a number of different adblocking lists.

Awesome, thanks, I will definitely check this out.

I used to have an old computer and a NAS, but they were too noisy.

I used the progress in CPUs in a different way: bought one of the fanless ITX sized computers and attached reasonably sized WD passport to it which is spun down most of the time (things are mostly served from an internal SSD)

I have similarly evolved my setup, initially a couple of 'midsize' towers and a StoreVault NAS, then the computers were replaced with a couple of Shuttle XPC type 'box' computers, then the NAS was replaced with a much quieter FreeNAS box from iXSystems, then the 'services' system (DNS, NTP, LDAP, Nagios, etc) was replaced with a couple of small ARM machines (initially Raspberry Pis but migrated to Odroids for performance reasons). And then the last XPC was swapped out for a fanless 'third height' ITX type system that is designed for home entertainment systems.

Realistically all of this could be built into a single hybrid of disk shelf and blade server box. That is something I've contemplated as the 'next generation' of the technology.

Why thermo-electric cooling instead of more efficient forced-air cooling?

or passive cooling with huge heatsink.

As it turns out, forced air cooling isn't as efficient as water is for carrying heat. As a result the most efficient way to cool a server is to put a water filled heat exchanger in front of it and let the computer's fans draw air through that into the chassis.

And that leaves you with how to dump the heat out of the water, and that is most effectively done (in a small scale) with thermo-electric coolers. You can add scale cooling very effectively by turning on additional coolers. My design is pretty simple, the reservoir tank is on top of the rack and there is a heat exchanger on the bottom and one in "front" of the CPUs. As they draw air through the heat exchangers the water warms and rises to the top where the reservoir is, and the chilling water in the reservoir naturally sinks back down to the bottom where the first heat exchanger is.

You can think of it like a rack sized version of the liquid cooler you can put on an enthusiast PC these days. Its quiet, self contained, and quite efficient, while still being able to use forced air cooled server equipment. The goal being efficient cooling in a temperate climate (California Bay Area) that is quiet and can use surplus/old equipment that was originally slated for a data center without violating any of that equipment's assumptions about the environment it can count on.

>that leaves you with how to dump the heat out of the water, and that is most effectively done (in a small scale) with thermo-electric coolers

This is the part that sounds strange to me. Water cooling has its advantages, but the heat is almost always dumped from the water by pumping it through a radiator that has fans blowing air through it. What's the advantage of thermo-electric cooling here over the traditional method?

> What's the advantage of thermo-electric cooling here over the traditional method?

1) It is quiet

2) It is easily electronically controllable based on the heat load in the water.

The heat sinks on the thermo-electrics are convection cooled and you could blow air over them but as you increase the thermal gradient between the heat sink and the air around them you are able to dump more heat. The only parameter you can vary with the typical heat exchange is "blow more air" you can't change the working temperature of the exchanger.

That said, the way power plants cool their water is in big evaporative cooling towers, but since I don't need a humidifier for the lab I stick with just convection cooling :-)

Are you talking about using Peltier devices when referring to "thermo-electrics" here?

Yes. I bought a bag of 12V ones at a local surplus shop.

I had something similar to this on my old P4x rig had watercooling with the radiators mounted horizontally outside the case, made a thermal controller for the fans and most of the time they where stopped or at maybe 40% speed, only with heavy loads they went faster. Now i have an arcooled I7 and the fans drive me nuts.

I've spent a fair amount of time this year with liquid cooling designs, and final parts are coming in to do something along the lines of what you're talking about. Do you have any blog posts/videos walking through this? It sounds really interesting and I'd love to see it.

> As a result the most efficient way to cool a server is to put a water filled heat exchanger in front of it and let the computer's fans draw air through that into the chassis.

What standard are you using for "efficient"? Thermo-electric coolers are neat, but the last thing they are whatsoever is efficient from a power-usage stand point.

If you're doing chilled water cooling, the only real option to consider is a mechanical heat pump (e.g. the ones in a refrigerator), but even that is silly. Hardware doesn't mind being somewhat warm, and using ambient air for cooling is far more efficient then either.

There's a reason thermoelectric refrigerators aren't really a thing. Peltiers are horrible. Mechanical heat pumps easily achieve twice the efficiency or more.

> What standard are you using for "efficient"?

PUE

Why the hell are you using peltiers, then?

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