Been thinking about setting up a NAS but already have a Mac mini? You're basically halfway there. While dedicated NAS boxes have their place, your Mac mini can handle home file serving duties just fine—especially if it's not your daily driver anymore.
The beauty of using a Mac mini as a NAS is simplicity. No learning proprietary interfaces or dealing with Linux command lines unless you want to. Just macOS doing what it does best: making things work.
What You'll Need
First, the obvious stuff. You'll want external storage—either a single large drive or multiple drives depending on your setup. USB-C and Thunderbolt drives work great with modern Mac minis, though USB-A is fine too if that's what you've got.
For drives, think about whether you want redundancy. A single 4TB drive might be fine for media storage, but if you're backing up family photos, consider RAID 1 or just buy two drives and set up Time Machine to one of them. Your call on how paranoid you want to get.
Network-wise, you'll want your Mac mini connected via ethernet if possible. Wi-Fi works, but wired is more reliable for file serving. Most people have their router near their entertainment center anyway, so this usually works out.
Setting Up File Sharing
macOS makes this pretty straightforward. Head to System Preferences > Sharing and enable File Sharing. You can share specific folders or entire drives—whatever makes sense for your setup.
Create a dedicated user account for network access if you want to keep things tidy. This isn't strictly necessary, but it's cleaner than using your main account for file serving. Set a strong password since this will be accessible over your network.
For the shared folders, you can set different permissions for different users. Maybe the family gets read/write access to the media folder, but only you can write to the backup directory. Standard Unix permissions apply here, nothing fancy.
Remote Access and Security
If you want to access your files from outside your home network, you've got options. The simplest is using macOS's built-in Screen Sharing, but that's overkill for just grabbing files.
VPN back into your home network is the secure approach. Many routers support this, or you can set up macOS's built-in VPN server. Avoid opening file sharing ports directly to the internet—that's asking for trouble.
For local access, SMB sharing works with pretty much everything: Windows PCs, other Macs, even your phone. AFP is Mac-only but can be faster between Mac devices. Enable both if you're not sure what your future devices will be.