What a home server is
A home server is a computer that stays on and does jobs for everyone in the house. It might block adverts on every device, keep a copy of your phone’s photos, play your films on the TV, or run a Minecraft world for your friends. Nobody sits at it: you reach it from a browser or a phone app, and it sits quietly next to the router.
These jobs are light, so almost any computer from the last decade is enough. That is why the best first server is one you already own: it costs nothing, and if you outgrow it, you’ll know exactly what to buy next.
Which spare machine to use
If you have more than one candidate, this is how they compare:
| Machine | Electricity | Room for drives | Worth knowing |
|---|---|---|---|
| Old laptop | Low | One inside, more over USB | Screen, keyboard and battery built in |
| Old desktop | Higher | Several | Easy to open, upgrade and repair |
| Raspberry Pi | Lowest | USB, or an add-on board for an SSD | A different kind of chip, so some systems and apps won’t run |
| Your everyday computer | What it already uses | What it has | Apps stop whenever it sleeps |
Choose the one with the most memory and an SSD, then measure what it really draws with a plug-in meter. The power, noise and UPS page shows how to turn that into a yearly cost.
What it needs
Check these before you start. None of them needs special tools.
- A 64-bit processor. Almost every computer from the last ten years has one. Some very old netbooks don’t.
- At least 4 GB of memory, and 8 GB if you can. ZimaOS, the easiest server system, asks for 4 GB and recommends 8 GB.
- An SSD. A spinning hard drive works, but everything starts and responds more slowly. Swapping in a SATA SSD is the cheapest big upgrade for an old laptop.
- A network port. A cable to the router is far steadier than Wi-Fi. If the laptop has no port, a USB network adapter usually works.
- Starting from a USB stick. That’s how you install a server system, and every PC from the last decade can do it.
To see what’s inside a Windows computer, open Settings, then System, then About for the processor and memory. The Performance tab in Task Manager says whether each disk is an SSD or an HDD. On a Mac, open the Apple menu and choose About This Mac.
Old Macs are a special case. Intel Macs without Apple’s T2 security chip, which means most models from before 2018, take Linux much like any PC. Macs with the T2 chip make Linux awkward, and Macs with Apple’s own chips can’t run ZimaOS at all. Keep those on macOS and use them as a test bench.
How an old laptop fits in
- A battery that acts as a UPS. It keeps the server running through a short power cut, the job a separate battery box does for a desktop.
- A screen and keyboard attached. When something goes wrong, you can read the error without finding a monitor.
- Low power. Laptops are designed to run on a battery, so they draw a fraction of what a desktop does while idle.
- Quiet. Light server jobs barely make the fan spin.
- Video conversion built in. Intel laptops from the last decade have Quick Sync, a part of the chip that converts video, which media servers such as Jellyfin use to play films smoothly on phones and TVs.
Three things to sort out before it becomes a server:
- The battery. If the BIOS or the maker’s app offers a charge limit, turn it on so the battery isn’t held at full charge for years.
- The lid. Most server systems, ZimaOS included, put a laptop to sleep when the lid shuts. The no-terminal answer is to leave it open, which also helps it stay cool. Changing the setting means editing a file from the terminal.
- Its contents. Installing a server system erases the disk, so copy off anything you want to keep.
For an old desktop, look in the BIOS for a setting called Restore on AC power loss or After power loss, and set it to Power on. The server then starts again on its own when the power comes back.
The easy way to set it up
You don’t need the terminal. ZimaOS is a free system made for home servers, and everything after the install happens in a web page:
- Back up anything on the spare computer that you want to keep.
- Make a USB stick on your everyday computer with ZimaOS USB Creator. If that won’t run, balenaEtcher does the same job with the installer file from ZimaOS’s releases page on GitHub.
- Change two BIOS settings on the spare computer: turn UEFI boot on and Secure Boot off.
- Start from the USB stick and install ZimaOS onto the internal drive, which needs at least 25 GB.
- Open the address it shows in a browser on another device, create your account, and install apps from the App Store.
The free plan covers 4 disks and 3 user accounts, which is plenty for a laptop. The server operating systems page compares ZimaOS with the alternatives, including the terminal route with Ubuntu Server.
A Raspberry Pi can’t run ZimaOS, because it uses a different kind of chip. It runs Raspberry Pi OS, which the official Raspberry Pi Imager app writes to a memory card, and the same page explains how to add an app store to it.
If you want to keep using the computer as it is, many apps also come as ordinary Windows programs, and Docker Desktop runs the rest. Set the computer never to sleep while it’s plugged in.
Questions people ask
How much will it cost to run?
It depends on how many watts the machine draws and what you pay per kilowatt-hour. A plug-in power meter tells you the first, and your electricity bill tells you the second. Laptops and mini PCs are cheap to leave on all year; old desktops and gaming PCs much less so.
Can I keep using it as a laptop?
Not once a server system is installed: it wipes the disk and has no desktop. If you still need it as a laptop, keep Windows and accept that its apps stop when the lid closes.
Is it safe to leave a laptop on all the time?
Generally, yes, if it can breathe. Keep the vents clear and don’t stack things on it. Check the battery every few months for swelling: a keyboard or trackpad that lifts, or a case that won’t sit flat. If you see that, stop using it and have the battery removed and recycled. Many laptops then run on the charger alone.
Is 4 GB of memory enough?
For one or two small apps such as an ad blocker, yes. Media servers, photo backups and game servers each want more, and 8 GB is comfortable for a handful of apps. Some laptops let you add memory, but in many thin ones it’s soldered to the board, so check before you buy any.
When should I buy something instead?
When the spare machine is too loud, too power-hungry or out of memory for what you want to run. A used business mini PC is the usual next step, and the buying guide explains what to look for.
