**TL;DR**Basically, any computer that you have previously used as a workstation (for example, an old laptop) can become a server. If it doesn’t have an Ethernet port, get an adapter (PCIe Ethernet for a desktop, USB-Ethernet adapter for a laptop). Depending on the scale of your operation, even single board computers like a Raspberry Pi can work, but remember: the only ethical hardware is second hand hardware. Except for hard drives, don’t buy second hand hard drives.

There are a few factors that go into choosing the correct hardware for your project, mainly:

• Budget/availability
• Use case
• Environmental Footprint

The more concurrent users you expect (people that are accessing the server at the same time) the better your hardware needs to be. That being said, most web apps are not very compute intensive and rather rely on having a lot of RAM and the ability to process a lot of requests in parallel—CPUs with multiple cores are definitely beneficial here.

Most well refined systems use PHP, an old and reliable programming language for the web that is part of most websites on the internet today. However, since it is an old programming language, it is not very well optimized for a lot of parallel users. Most services that you might want to run on your server specify minimum system requirements, so it’s probably good to read up on a few before making a choice.

Basically any computer can be turned into a server, even an old smartphone! For very old or very small computers, you will have to assess if they are fast enough for what you have in mind. If you are reading this guide, any working old laptop is probably enough.

Some people like to work with single board computers (SBCs), like Raspberry Pis. While a Raspberry Pi will reach its limits quite quickly if you plan on running several services at the same time, there are other single board computers that are much more powerful and can handle ever larger jobs. Single board computers are often relatively cheap, use very low amounts of energy, and come in a small and convenient form factor.

If the form factor is not important, however, we recommend using an old laptop. Due to much fewer restrictions in terms of size, even an old laptop will likely outperform a new single board computer. The built-in battery, if it is still functional, can protect against fluctuations in the power grid. The built-in screen and keyboard, if still functional, eliminate the necessity for additional peripherals during set up and allow direct interaction with the machine. Due to their portability, laptops are usually designed to be much more power efficient than desktop machines. If you or someone you know doesn’t already have an old laptop that you can use, chances are you can find one for free or very cheap online.

It takes a lot of energy to build computers, and buying new hardware has a big impact on the environment. Even the most energy efficient new computer will not be able to offset the amount of energy that had to be used in its production. We strongly encourage everyone to consider used hardware wherever possible. A used laptop will always be more environmentally friendly than a new Raspberry Pi!

While it’s certainly possible to install Linux on an old Apple computer like an old MacBook, and to turn it into a server, Apple has complicated this process significantly (basically: the newer the computer, the more hurdles you will have to overcome). Because the process changes so much depending on your model, we currently have not included a manual for how to install Linux on old Apple computers.

For the purpose of this guide, we will assume that you have access to an old Windows or Linux computer, as these are much easier and cheaper to come buy than old Apple computers. If you do have an Apple computer which you want to install Linux on, there are many guides such as this one which will walk you through the installation process. After the installation process is complete, you should be able to follow the guides in this manual as usual.

No matter what hardware you chose, you will often need to add additional storage, for example if you want to set up a file sharing service where each user has multiple Gigabytes or even Terabyte of storage allocated to them. But also in other cases, it’s quite common to use different storage options for different purposes. A classic solution would be to use a small but fast disk to run your operating system from, and to save all the user data on a bigger, but potentially slower drive. There are multiple considerations here, but mainly it boils down to speed, capacity, durability and expense.

HDDs are very cheap but slow and not durable. SSDs are fast and reliable, but expensive. In most cases, a hybrid solution is the most efficient: run the system on a small SSD that is fast and reliable, and store all data on multiple large and cheap HDDs.

The main types of storage are Hard Disk Drives(HDD) and Solid State Drives (SSD), though some single board computers also work with other storage mediums like flash drives or SD cards. While those are ok for testing and tinkering, it is not recommended to run a server that uses an SD card as data storage—SD cards deteriorate with every read/write operation, and they will fail eventually, leading to downtime and potentially data loss. It is possible to use an SD card to boot the system from, but to set it to read-only, and store all relevant data on another volume, but this is something that we will not cover in this guide as it is a bit of an edge case.

Hard Disk Drives have been around for a long time. Simply put, they operate similar to a CD or DVD, with all data stored on a physically spinning disk. They are the slowest, type of storage, but also the cheapest. They are very big in comparison to other solutions and not very durable: Hard drives have a limited amount of read/write operations they can do before they will inevitably die, and when they do, they probably cannot be fixed without spending a considerable amount of money. Most servers are always on and especially when you have multiple users, this means that your hard drives will undergo a lot of read/write operations. The question is not if an HDD will fail, but when.

There are server-grade HDDs which are more resistant to wear, but cost more money. For the scope of self-hosting, those are probably not required, though. Even under continuous use, a new HDD should last a few years, and there are setups to prevent data loss even in case of an HDD dying.

While we recommend buying used hardware wherever possible, we don’t recommend this with HDDs.

> The longer a hard drive is in use, the more likely it is to fail. With used hard drives, it’s difficult to know how much life they have left in them. There is also a chance that the second hard drives you find online have been used in crypto mining at some point, further increasing the likelihood of failure in the near future.