The hardware question is one of the first things people get stuck on when thinking about a home server. There’s an instinct to either over-engineer it — a rack-mounted NAS, multiple drives in RAID, something that looks impressive — or to under-build it on a Raspberry Pi and spend the next six months fighting its limitations. Neither is necessary.

The most useful thing a home server can be is forgettable. You set it up, it runs, and you stop thinking about it. That points pretty directly at what to look for.

Why a second-hand business PC#

Consumer hardware is designed around a different set of assumptions than a machine you want running continuously. It’s built to be fast when you need it and quiet when you don’t, with the expectation that it gets turned off at night. Business hardware is built to run all day, every day, in an office environment. The reliability expectations are higher, the thermals are designed for sustained load, and the build quality reflects that.

Mini PCs from the business world — the Lenovo ThinkCentre Tiny range, HP EliteDesk Mini, Dell OptiPlex Micro and similar — are a particularly good fit. They’re compact, they idle at around 10 to 15 watts, they’re quiet enough to live in a cupboard, and they were built to last. Critically, they come off corporate lease cycles in large numbers, which means the second-hand market is well stocked and prices are reasonable.

The machine used for this series is a Lenovo ThinkCentre M920q, picked up second-hand for around £130. An Intel i5, 8GB RAM, 256GB SSD. For the job it’s doing, it’s massively overpowered — and that’s exactly right.

Overpowered is fine. Underpowered is a problem.#

A server that’s working hard all the time is one that’s running hot, wearing out components faster, and leaving no headroom for anything new. A server that’s barely breaking a sweat at idle has years of comfortable life ahead of it, and plenty of room to take on additional services without complaint.

The i5 in the ThinkCentre mostly sits doing very little. When a backup runs, or a batch of photos gets processed, it picks up the load and drops back down. That’s the ideal pattern.

What actually matters in the spec#

RAM matters more than CPU for the kind of workload a home server typically handles. Running several Docker containers simultaneously is more about keeping things in memory than raw processing speed. 8GB is workable, 16GB gives comfortable headroom. Beyond that, for typical home use, you’re unlikely to feel the difference.

Storage is worth thinking about in layers. The system drive — the one the operating system and application configs live on — doesn’t need to be large. 256GB is plenty. Data storage, where your files and photos actually live, is separate and can be expanded independently. An external USB drive works fine for this, and keeps your data separate from your system in a way that makes backups and future migrations much simpler.

The operating system#

Ubuntu Server is a sensible default for this kind of setup. It’s stable, well documented, and the vast majority of self-hosting guides assume it. There’s nothing exotic about the choice — it just gets out of the way and lets you focus on the things running on top of it.

One concept worth understanding early is Docker. Rather than installing applications directly onto the server, Docker lets you run each one in its own isolated container. Think of it as each service living in its own clean environment, with its own dependencies, separate from everything else. This makes installation, updates, and removal much cleaner, and it means a broken service can’t drag down the rest of the system. Most modern self-hosted applications are distributed this way, and once the pattern clicks it becomes the obvious way to run things.

The unglamorous reality#

There’s nothing exciting to say about the hardware side of this. A modest, reliable machine running a stable operating system is the foundation everything else depends on. The interesting work happens in the layers above it.

That’s the point. Boring hardware, running quietly in a cupboard, is exactly what you want.