The Mac Mini is a fantastic compact computer from Apple and even the base model has enough system resources to handle some heavier tasks. Thankfully, Apple moved away from offering just 8GB of RAM. Running macOS, the Mac Mini can be configured to open up file access to clients on the network. Turning it into a NAS will keep your old Mac Mini out of the house waste system and save you money on hardware.

Why use a Mac Mini as a NAS

There are many options when shopping around for a pre-built NAS enclosure. Brands such as Synology, Asustor, and TerraMaster offer different models with varying specifications. These are excellent for those new to the world of NAS, but if you already have hardware available, such as a Mac Mini, it's better to re-use the tech and create a DIY NAS. This powerful compact system has everything you need for home or office-based network storage, including a LAN port (don't rely on the wireless), internal storage, and a few USB ports.

It gets even better if you have a Mac Mini with Apple silicon as the chips are incredibly energy efficient and will work well for lighter and heavier loads. One area in which the Mac Mini fails is internal storage since you won't be able to upgrade it. A workaround for this shortcoming is the addition of an external drive enclosure, known as direct-attached storage (DAS). Installing a few drives inside this enclosure would expand the storage pool of the Mac Mini with nothing but a single USB connection. It's best to use external drives to store lots of data and avoid wear on the Mac Mini primary drive.

MacOS can also be configured to run like a NAS OS and you can easily install apps from the App Store, such as Transmission. This would allow you to use the Mac Mini as a file downloader, which can come in handy for larger files on slower connections to save your desktop or laptop PC needing to be switched on.

How to set up your Mac Mini as a NAS

Before setting everything up on your Mac Mini, I recommend you reinstall macOS and start anew. This guide will get you up and running from start to finish in no time.

Reinstall macOS

1. Power off the Mac Mini.
2. Enter macOS Recovery:
   • Apple: Press and hold the power button, select Options, and click Continue.
   • Intel: Power on the Mac Mini while holding CMD + R.
3. Click Disk Utility.
4. Choose your primary internal drive.
5. Click Erase.

6. Name the new drive "Macintosh HD".
7. Set the format to APFS or Mac OS Extended.
8. Click Erase.
9. Close Disk Utility.
10. Click Reinstall macOS.
11. Click Continue.
12. Follow the macOS installation wizard.

Once macOS has successfully installed, it's time to prep the OS for file sharing.

Set up macOS for sharing

Configure your internal and external storage accordingly, creating a redundant array of inexpensive disks (RAID) and storage pools for storing and sharing data between clients. Then we can start activating protocols and services.

1. Go to Apple > System Preferences.
2. Go to General.
3. Give your Mac Mini NAS a name in the Name field.
4. Go to Sharing.
5. Enable File Sharing.
6. Click the info icon.
7. Click + under Shared Folders to select a folder/volume.
8. Set permissions for each user/group:
   • Read Only: The user/group can view the contents but not write data.
   • Write Only (Drop Box): The user/group can write data but not view contents.
   • Read & Write: The user/group can both see and write data in the Shared Folder.
   • No Access: The user/group is unable to view the Shared Folder.
9. Click Options.
10. Check the Share files and folders using SMB box.

With the Shared Folders configured and File Sharing enabled, the Mac Mini will now show up on client devices when searching for hardware on the network. The computer name field is important since it will be displayed to clients, so make sure it's unique and descriptive of what the Mac Mini NAS will be used for.

Connect to your Mac Mini remotely

Once your Mac Mini is up and running as a NAS, you'll likely want to hide it out of the way, especially when using a DAS or external drive. This may put the device out of reach of your keyboard, mouse, and display. To remedy this, we can configure macOS to accept remote desktop and screen-sharing connections. This will allow you to connect to the NAS from any room in the building.

1. Go to Apple > System Preferences.
2. Click General > Sharing.
3. Enable Screen Sharing.
4. Click the info icon.

You can now configure the Screen Sharing with a password and whether anyone can connect to the Mac Mini. Using a VNC viewer, almost any device on the network would be able to connect to the Mac Mini and control macOS without physically being tied to the NAS.

Remember to use NAS drives!

If you're connecting an external drive or enclosure to the Mac Mini NAS, be sure to use NAS-rated drives. Standard HDDs and SSDs, including the one inside the Mac Mini, aren't designed for long-term NAS use. I recommend reserving the internal storage of the Mac Mini for apps and OS, leaving data storage and the like to external drives. Seagate IronWolf and Western Digital Red are two reliable NAS drive families with plenty of capacities (and prices) to choose from.